emqtt's transitive `quicer` dep needs CMake + msquic submodule
clones to build, which the slim Debian builder image doesn't ship —
the prod CI build was failing inside `mix deps.compile`. Tortoise311
is the obvious pure-Elixir alternative but it bundles a
gen_state_machine + retry/inflight stack we don't use because we're
subscribe-only at QoS 0.
Implementing the wire protocol inline is ~150 lines in
`Microwaveprop.Pskr.Mqtt` (CONNECT/SUBSCRIBE/PINGREQ/DISCONNECT
builders, CONNACK/PUBLISH/SUBACK/PINGRESP parser, varint codec).
Pskr.Client now uses :gen_tcp with `active: :once` framing,
buffers partial reads, schedules its own keepalive, and parses
inbound packets in a tight loop.
Drops `BUILD_WITHOUT_QUIC=1` from the Dockerfile — no longer
relevant since there's no native dep at all in the build chain
now.
Subscribes to mqtt.pskreporter.info:1883 over plain TCP and folds
every reception report into hourly aggregates per
(band, sender_grid_4, receiver_grid_4). Each spot is the empirical
"propagation actually occurred on this path right now" signal we'll
correlate against HRRR atmospheric state to recalibrate the scoring
weights. Aggregating at the path-hour bucket collapses 50-reporter
QSOs to one row instead of 50.
Topic filter anchors on USA (DXCC 291) on either sender or receiver
side so the broker pre-filters out everything outside our HRRR
domain. Bands subscribed: VHF and up (6m, 2m, 70cm, 23cm, +
microwave) — HF is dominated by ionospheric propagation, which this
project doesn't model.
Pskr.Client cluster-elects a singleton via :global.register_name —
all replicas start the GenServer but only one connects to MQTT;
the rest stay in :standby and watch for the leader's nodedown to
re-run election. Off in dev/test, on by default in prod
(PSKR_MQTT_ENABLED=false as kill-switch).
Pskr.Aggregator buffers in memory keyed by Pskr.path_key/1 and
flushes every 60s via Repo.insert_all/3 with an additive
ON CONFLICT (count summed, SNR envelope by GREATEST/LEAST,
modes unioned via unnest+DISTINCT). Idempotent across overlapping
flushes and across leader handover.
Dockerfile sets BUILD_WITHOUT_QUIC=1 — emqtt's transitive quicer
dep wants CMake + OpenSSL headers we'd otherwise have to add to
the builder image just to never use QUIC over plain MQTT. Base
image is unchanged; the new dep compiles cleanly into the existing
prop-base runtime.
phoenix_pubsub_redis 3.1's deprecation message ('Move :url inside the
:redis_opts option') is misleading — wrapping the URL as
`redis_opts: [url: url]` forwards the keyword list to Redix, which
rejects `:url` with `unknown options [:url], valid options are:
[:host, :port, :password, ...]`. New pods on commit b4d6b04 onward
crashed at startup with that NimbleOptions.ValidationError; old pods
running e53a34d (top-level :url) coasted on already-established
connections so the breakage only surfaced when fresh pods rolled.
The library accepts `redis_opts` as either a URL binary OR a
keyword list. Pass the URL as a bare string so it takes the
binary-clause path that hands it directly to Redix.PubSub.start_link/1.
The library deprecated top-level Redis connection keys; passing :url
directly logged a warning on every boot. Functionally identical, just
silences the warning.
Switches the PubSub adapter to Phoenix.PubSub.Redis backed by the
shared Valkey instance (same backend GridCache uses), via the new
phoenix_pubsub_redis dep. Falls back to the default PG2 / Erlang-
distribution adapter when VALKEY_URL is unset, so dev/test boot
unchanged.
Decouples PubSub fan-out from libcluster's BEAM connection. A
flapping Erlang distribution (the OOM-cascade scenario from
2026-05-03 surfaced this — libcluster warnings dominated the logs
while pods CrashLoopBackOff'd) no longer takes broadcasts with it,
so the rest of the cluster keeps publishing while the bad pod
recovers.
node_name uses POD_IP for cluster-wide uniqueness, falling back to
Erlang's node() name in non-K8s environments. Required by the Redis
adapter so loopback filtering doesn't drop a pod's own broadcasts as
if they came from a peer.
Each cached HRRR valid_time is ~32 MiB compressed × cap of 8 = up to
256 MiB per pod. With 4 hot pods + 1 backfill that's ~1.25 GiB of
cluster RAM holding identical content. Replacing the per-pod ETS
replicas with a single shared Valkey copy collapses that to ~256 MiB
total (off-pod) and makes the BEAM heap on each replica meaningfully
smaller — directly addresses the headroom the 2026-05-03 OOM cascade
ate into.
* New `Microwaveprop.Valkey`: single Redix connection (named conn,
sync_connect: false, exit_on_disconnection: false). `start_link/0`
returns `:ignore` when VALKEY_URL is unset so dev/test boot without
Valkey. Helpers wrap GET/MGET/SET-with-TTL/ZADD/ZREVRANGE/SCAN with
`:erlang.term_to_binary` round-tripping under the safe atom flag.
* `Microwaveprop.Weather.GridCache` now branches on
`Valkey.configured?/0`. Public API is identical so callers (Weather,
GridCachePruneWorker, MapLive) don't change. ETS path is preserved
unchanged for dev/test.
* Storage layout when on Valkey:
prop:wg:vts ZSET of valid_time iso8601 strings
prop:wg:<vt>:<lat>:<lon> one chunk per 5°×5° spatial bucket
fetch_bounds MGETs only the chunks intersecting the viewport, so a
regional view is 1-4 round-trips instead of pulling the full grid.
* Per-key TTL = 8 h (matches the ETS valid_time cap). Eviction is
automatic; prune_keep_latest is a no-op on Valkey, prune_older_than
uses ZRANGEBYSCORE + DEL.
* All Valkey errors fall back to disk (ScalarFile.read_bounds), logged
as warnings — page works through Valkey outages, no user-visible
break beyond a one-shot latency bump.
ScoreCache, Microwaveprop.Cache, NexradCache, telemetry/Postgres
protocol/libcluster registry tables remain ETS — they're sub-ms
hot-path lookups where a network hop would be felt.
VALKEY_URL must be present in prop-secrets for production rollout
(applied out-of-band, secret.yaml is git-ignored).
Found while auditing pod memory: :weather_grid_cache is by far the
largest ETS table (~32 MiB compressed per entry, vs ~2 MiB/entry for
ScoreCache) because each cell is a 22-field weather row instead of a
scalar score. Cap of 24 meant the cache could hoard up to ~768 MiB on
a single pod, and hot pods sit at 3-5 GiB against a 6 GiB limit — most
of that headroom belongs to GridCache.
The cap was sized for 'analysis + 18 forecasts + stragglers' but the
real access pattern is current-hour + a short forward scrub. Beyond
that, fall back to ScalarFile.read_bounds (sub-100 ms per file) instead
of permanently parking ~500 MiB on data nobody looks at.
Worst-case GridCache spend drops 768 MiB → 256 MiB. Steady-state win
is smaller (most pods don't fill all 24 slots), but bounds the tail.
Each path-table cell now wraps its content in <.link navigate={...}>,
so the row behaves as a native anchor: hovering shows the destination
URL in the browser status bar, right-click 'open in new tab' works,
middle-click works, and the rendered HTML is meaningful to assistive
tech / scrapers / link-validators.
Replaces the phx-click={JS.navigate(...)} pattern, which gave none of
those affordances and required the user to trust that the row was
clickable. Whole-row hover highlight is preserved via a CSS
:has(a:hover) selector so cell-hover still tints the row.
The /rover-planning index was rendering only band_mhz (the legacy
primary single-band column), so multi-band missions with bands_mhz
populated showed just the first band. Switched the renderer to
arity-2 and now pulls the full bands list via Mission.bands/1, so
multi-band missions render '10 GHz · 24 GHz · 47 GHz' etc. Sort
still keys on band_mhz so the column stays sortable on a single
scalar value.
The default 'We can't find the internet' wording blames the user's
connection, but the typical cause on this site is a server-side issue
(deploy in progress, pod OOM, ingress hiccup). Server-specific wording
matches reality and points users at the right thing to wait on.
The :terrain queue at 3 slots/pod was sized for the lightweight per-QSO
TerrainProfileWorker, but RoverPathProfileWorker now runs the full
PathCompute pipeline (terrain + 9 HRRR profiles + sounding + ionosphere
+ scoring + loss + forecast) — same heap profile as :propagation, which
sits at 1 slot precisely to avoid OOM.
A backfill_paths flood today queued ~200 rover-path jobs. With 4 hot
pods × 3 slots, the cluster stacked 15 concurrent path-computes and
two pods OOM-killed in a loop, taking the libcluster ring with them
(visible as the "unable to connect" warnings on the surviving pods).
New :rover_path queue at 1 slot/pod caps cluster-wide concurrency at
(hot_replicas + 1 backfill), drains the existing 200-job backlog
inside ~30 min, and keeps :terrain free for the cheap workers it was
sized for.
Existing Path rows persisted before the PathCompute extraction shipped
have no "term" key in their result map, so the live /path page hits
the :stale_term branch and falls back to live recompute when the
operator clicks a row. The hourly backfill cron now flips those
:complete rows back to :pending so the path-profile worker rerolls
them with the new full-output term, after which row clicks render
from cache instantly. The flip uses Postgres's jsonb_exists() so it's
a single targeted UPDATE instead of pulling rows into Elixir.
Two stacked wins for the form-submit hot path:
1) create_mission now hands path-matrix population to the same async
reconcile worker update_mission uses, so the request returns
right after the Mission row insert. For a mission with hundreds
of (rover x station x band) tuples this used to block the LiveView
for many seconds.
2) Inside reconcile/enqueue_paths_for, the per-pair Multi.insert
loop is replaced with one Repo.insert_all for the Path rows and
one Oban.insert_all for the worker jobs. N round-trips collapse
to two regardless of pair count.
Three connected changes:
1) Extract PathLive.compute_path/4 + every helper it owned (resolve,
profile grid lookup, sounding/ionosphere readouts, scoring, loss /
power budgets) into Microwaveprop.Propagation.PathCompute. PathLive
now delegates; ~410 lines of dead helpers deleted from PathLive.
2) RoverPathProfileWorker calls PathCompute.compute/4 with the
mission's heights and PathLive's default station params (10 W TX,
30 dBi gains). Stores the full atom-keyed compute output as a
Base64-encoded :erlang.term_to_binary/1 blob alongside the flat
summary fields the rover-planning show table reads. The blob
roundtrips structs and DateTime exactly (Jason.encode would lose
them).
3) PathLive accepts ?rover_path_id=UUID. When set, loads the cached
Path, decodes the term (binary_to_term :safe), assigns it as
@result, and renders normally — no compute_path call. The
rover-planning show table now links rows directly to
/path?rover_path_id=UUID, so a click opens the full Path
Calculator UI from cached data without re-running terrain / HRRR /
sounding lookups.
Bonus prod fixes folded in:
- PathShow's elevation chart attribute (data-* → data-profile JSON)
was crashing the JS hook with 'unexpected character at line 1'.
- Station.changeset now wipes previously-resolved callsign/grid/
lat/lon when the user types into :input — typing 'AA5' early
resolved to a wrong location and locked it; subsequent keystrokes
never re-resolved.
- phx-debounce=600 on the station input so QRZ doesn't get hit on
every keystroke.
Worker now stores the full per-point analysis (beam height,
Fresnel-zone radius, clearance) on Path.result.path_points, and
PathShow renders a real cached page: terrain elevation chart fed by
the same ElevationProfile JS hook /path uses (feet on Y, miles on X,
LOS + Fresnel overlay), distance / bearing / clearance / antenna
heights all in feet, baseline link-budget breakdown, and the cached
midpoint propagation score with computed_at timestamp.
A Recompute live button hands off to /path for the time-varying bits
(current HRRR conditions, scoring breakdown, sounding, ionosphere)
that aren't worth caching.
The cached path-detail URL was a thinned-down view (geometry +
loss-budget summary + score). The user wanted the same rich display
/path renders — terrain chart with feet axes + tooltips, conditions,
scoring, link/power budgets, forecast — so PathShow now resolves the
row's rover/station/band/heights and push_navigates to /path with
those params baked in. The cached result map on Path.result is still
what the rover-planning show table reads from for fast row rendering;
this just bridges the row click to the canonical Path Calculator.
The whole-block try/rescue around fetch_stats meant any single failing
query (a missing dev table, a transient pg blip) zeroed all 10
counters. Each count_exact/1 + count_estimate/1 now uses Repo.query/2
and falls back to 0 only for its own column. Bumps the inline 9-factor
prose to 10-factor and pulls the contacts headline from the live count
instead of a stale '58k+' string.
Adds a CLAUDE.md note prompting future updates to refresh /about's
prose when factor counts, data sources, or schema scale change.
New /rover-planning/:id/paths/:path_id route renders the worker-stored
result map directly: geometry, link-budget components, propagation
score, computed_at. The 'Recompute live' button hands off to /path
when the operator wants HRRR-driven loss against current weather.
Two fixes:
1) Form save / rover-site add/remove no longer runs the path-matrix
reconcile inline. update_mission and the show LiveView now
enqueue a single RoverMissionReconcileWorker job and return —
for missions with many rover sites x bands the inline path was
firing hundreds of Multi inserts + Oban.inserts on the request.
2) RoverPathProfileWorker.load_path/1 now strictly matches a
4-tuple (mission_id, rover_location_id, station_id, band_mhz)
with band_mhz as an integer, plus updates the Oban unique key
set to include band_mhz so multi-band missions enqueue per-band
jobs (not just one). Legacy/malformed args are logged and
dropped instead of crashing the queue with MultipleResultsError.
Clicking the trash icon on a stationary station in :edit mode before
any other phx-change had fired emptied the form's stations params,
which combined with cast_assoc(on_replace: :delete) wiped EVERY
existing station instead of just the one the user clicked. Fall back
to rebuilding the params from the persisted mission's stations when
the form's current params don't already carry them, then delete only
the targeted index.
Mission now carries bands_mhz ({:array, :integer}) — operator picks
one or more bands as multi-checkboxes. enqueue_paths_for builds the
cross product (rover x station x band) and persists each tuple as its
own Path row keyed by (mission_id, rover_location_id, station_id,
band_mhz). The path-profile worker reads band_mhz from the path
itself (legacy single-band jobs without band_mhz in args still resolve
to their unique row).
replace_mission_paths/1 is now a thin alias for reconcile_mission_paths/1
which diffs desired vs actual: stale tuples (old band that the user
unchecked, station they removed, rover-site they deleted) get dropped,
new tuples become :pending and enqueue, surviving :complete rows are
left in place — no more wholesale destruction of already-computed
paths on every edit.
The show table gains a Band column, and band_label() in the mission
summary becomes bands_label() (joins the list with commas).
The add-rover-site form now resolves the input on every change and, if
any existing rover-location shares the same 6-char Maidenhead cell
(~5 km), surfaces a 'Already saved as' link to that location's detail
page. Avoids users accidentally duplicating a site they (or another
operator) already added.
The path-profile worker now also computes the baseline link-loss
budget — free-space path loss, oxygen absorption, baseline H2O loss
(at 7.5 g/m^3 default humidity), plus the already-cached terrain
diffraction — and stores all four numbers in Path.result. The show
page renders the per-row total in a new Loss column. /path still
recomputes against live HRRR weather; this is the offline-readable
cached snapshot.
The 'Rover sites' card no longer renders the long list of every site —
each rover-location now appears once as a path-profile group heading,
which carries its own delete button next to the n/m progress text. The
add-site form stays in place.
Adds RoverPlanning.backfill_paths/0 that walks every mission and
re-enqueues RoverPathProfileWorker jobs for any (rover × station) pair
whose Path is missing or not :complete. The path-profile worker
short-circuits on :complete, so this is idempotent.
Wires a new RoverMissionBackfillWorker into both dev (config.exs) and
prod (runtime.exs) crons at HH:30 — heals missions stuck in :pending
or :failed from transient elevation-API errors or interrupted
create_mission enqueues without operator action.
The Stationary-stations summary was rendering whatever the user typed
verbatim ('aa5c 33.1889, -96.4517'). Switch to a pair of helpers that
uppercase the callsign (covering legacy mixed-case rows) and synthesize
a 6-char Maidenhead grid from lat/lon when no grid was stored. Bare
coordinates no longer appear in this list — the grid carries the same
location info in a more amateur-radio-native form.
The path-profile worker now also looks up the propagation grid score for
the path midpoint at the mission's band before flipping status to
:complete, so the row never appears 'done' until both terrain and
propagation prediction have run. The show table renders that score as a
red/yellow/green badge in a new Propagation column.
Each rover-location group heading is now a link to /rover-locations/:id
so the user can jump straight to the spot's detail page from the
mission view.
Path table now shows callsign on top with grid muted below, and the
detail-only Min clearance / Diffraction columns are gone. The verdict
badge matched lowercase 'clear/blocked/marginal' but the worker stores
uppercase 'CLEAR/BLOCKED/FRESNEL_PARTIAL/FRESNEL_MINOR' from
TerrainAnalysis, so every cell silently rendered empty. Updated the
guard clauses to the actual upstream strings and added Fresnel variants.
show.ex (rover-planning) and show.ex (rover-locations) auth + delete
flows go from nested case/case/case to a `with` ladder fed by a single
`authenticated/1` clause that returns `{:ok, user}` or
`{:error, :unauthenticated}`. The else block enumerates the small set
of failure tuples instead of rebuilding nested error returns.
Other idiomatic-Elixir tightening:
- `progress_summary/1` reduces with a `tally_path/2` multi-clause
helper (status as a head pattern, not three Enum.count passes).
- `paths_by_rover_location/1` extracts `group_to_pair/1`,
`station_position/1`, and `group_lat/1` so each transformation is a
pattern match instead of an anonymous fn with `&& fallbacks`.
- `error_summary/1` is two clauses (empty vs populated errors)
instead of a pipe-into-case.
- Drag-to-edit show.ex consolidates the working-coords assigns into
`assign_working_coords/3`.
Bug fix uncovered while writing tests: `add_station` on a fresh
/rover-planning/new form was a visual no-op on the first click —
cast_assoc replaced the unseeded default Station struct with the new
params row instead of appending. Now the initial changeset is built
from `%{"stations" => %{"0" => %{"position" => "0"}}}` so add_station
appends from the get-go. Regression test added at
test/microwaveprop_web/live/rover_planning_live_test.exs.
New test branches:
- form: add_station appends on first click + remove_station drops
the targeted row.
- rover-planning show: add_rover_site whitespace-input rejection,
delete_rover_site permission denial.
- rover-locations show: save_edit rejects unauthenticated drivers.
Suite: 3228 tests, 0 failures. Credo strict: 0 issues.
Owner / admin click "Edit" on /rover-locations/:id and the marker
becomes draggable. As they drag, the JS hook pushes `location_dragged`
events with the new lat/lon; the LiveView updates `working_lat` /
`working_lon` / `grid` so the page shows the live preview without
writing to the DB. "Save" persists via Rover.update_location, "Cancel"
reverts both the assigns and the marker position.
Implementation notes:
- Switched the map marker from L.circleMarker to a draggable L.marker
with a divIcon (CircleMarker has no `dragging` handler).
- A second `draggingDotIcon` (amber, larger, grab cursor) makes the
edit affordance obvious.
- Server <-> hook coordination uses push_event:
set_marker_draggable / reset_marker. Drag results come back on
pushEvent("location_dragged", { lat, lon }).
- Coordinates row binds to working_lat/working_lon so the displayed
decimals + derived grid update on every drag, not only on save.
A new "Rover sites" section between Stationary stations and Path
profiles lists the candidate rover locations the mission scores
against, with:
- An add form that takes the same flexible input as station inputs
(callsign, Maidenhead grid, or `lat,lon`); on submit it creates a
global :good rover-location and re-runs the path matrix.
- A per-row trash button visible to the location's owner / admins
that deletes the location and re-runs the matrix.
`RoverPlanning.candidate_rover_locations/1` is now public so the show
page can list exactly what the worker enqueues against. Add/remove
both call `replace_mission_paths/1` so the matrix stays consistent
with the rover-site set.
Anonymous visitors see a sign-in prompt instead of the form.
When a user types raw "lat,lon" coordinates into a station input,
LocationResolver populates only `lat` / `lon` — `callsign` and `grid`
stay blank. The path-profiles "Station" cell was falling through to
"33.189, -96.452" instead of showing a useful grid.
Now `station_label/1` (display) and `station_endpoint/1` (path-URL
destination) derive a 6-/8-char Maidenhead grid from the stored
lat/lon when no grid is on the row, matching the rest of the page's
grid-first presentation.
`Weather.nearest_native_duct_info/3` returns `{:error, :not_found}`
whenever the midpoint has no native HRRR profile within ±0.07° / ±1 h
— the documented fallback for the sparsely-populated
`hrrr_native_profiles` table (only QSO-worker-touched cells get
ingested). The empty-map fallback was already the right behavior; the
warning was just noise that fired on every /path computation outside
the populated set.
Now the `:not_found` clause silently returns the same fallback shape
without logging.
- Rows in each rover-location group are now phx-click handlers that
navigate to /path with source (rover-loc as 10-char Maidenhead grid),
destination (callsign > grid > coords), band, and rover/station
heights pre-filled — one click takes you to a ready-to-compute Path
Calculator screen.
- Station label now shows "AA5C · EM12kp" when both callsign and grid
resolved, instead of falling back to lat/lon. Bare-grid and
bare-coord stations keep their existing labels.
- Group heading uses Maidenhead.from_latlon(lat, lon, 10) so the
10-char grid is shown in full instead of being truncated to 6
characters.
The flat path table forced you to scan column 1 to mentally group rows
when standing at a specific rover spot. Each rover location now gets
its own card with a heading (grid + lat/lon + notes) and an inner
station-by-station table, so the paths to the fixed stations from the
spot you're at are read in one place.
Sorted by latitude (north → south) so the same location keeps the same
slot across re-renders. `rover_label/1` is removed (its content now
lives in the group heading).
- add_station no longer seeds `"input" => ""` in params, so used_input?/1
treats the new row as untouched and hides the validate_required error
until the user types.
- Show page's format_distance/format_db/format_meters helpers coerce with
`* 1.0` because JSONB returns bare zeros as integers, which crashed
Float.round/2 (FunctionClauseError on /rover-planning/:id render).
- Lat/lon row uses items-start + mt-6 trash so the inputs stay aligned
even when the callsign cell grows from validation feedback.
The hidden 'false' shadow input was rendered after the checkbox, so when
both were submitted the 'false' value overwrote the checkbox 'true' in
the resulting params map. Move the hidden input before the checkbox so
the checked value wins (matching the core_components checkbox pattern).
Adds a full-screen map view rendering every Good rover-location as a
green circle marker (popup links to the detail page). Uses the standard
OSM/Satellite + Maidenhead grid overlay pattern. Bad locations are
excluded. Adds a Map button next to Add location on the index header.
Renames the rover-location status enum and every label that referenced
it. Existing rows are migrated in place. Also touches the consumers:
- Rover.Location enum + default
- RoverLocationsLive index, status filter, form, show, badges
- Rover.Compute and rover_live (only_ideal_locations → only_good_locations)
- RoverPlanning context candidate filter (status == :good)
- RoverPlanning.Show / Form copy
- All rover-related tests
Adds a new globally-scoped, owner-mutable rover-mission tracker:
- /rover-planning paginated table (LiveTable) with View/Edit/Delete
- /rover-planning/new + /:id/edit form: name, band, antenna heights,
notes, "only check against known good locations" toggle (default on),
and a dynamic list of stationary stations entered as callsigns,
Maidenhead grids, or lat,lon pairs (Station changeset geocodes via
LocationResolver, lat/lon stays editable after add)
- /rover-planning/:id show page renders the station list, scope, and a
matrix of computed path profiles (distance, min clearance, diffraction,
verdict) populated as the worker completes each pairing
After save, RoverPlanning enqueues one RoverPathProfileWorker job per
(rover-location × station) pairing. The worker mirrors PathLive's
synchronous compute (ElevationClient + TerrainAnalysis at the mission's
band + heights) and stores the result on the matching path row.
PubSub broadcast on completion lets the show page live-refresh.
Admins can edit/delete any mission; owners can edit their own.
Adds start/end date inputs (UTC) to the sidebar (mobile + desktop) with
Apply dates and Clear buttons. The hook keeps a sliced YYYY-MM-DD on
each line entry so the range check is a string compare during filter
re-application; combines with the callsign filter so e.g. AA5C between
2025-01-01 and 2026-01-01 is one query.
Bare-input phx-change wasn't reliably delivering the value to the
filter_callsign handler. Wrapping the input in a form with phx-submit
+ a Filter button gives explicit submission (Enter or click) on top
of the existing debounced live filter.
Rover.update_location/3 and delete_location/2 now resolve any record
when the actor is_admin. The index + show LiveViews surface Edit/Delete
on every row for admin users, matching the existing owner UX.
Each row now has a View link (and the location cell links too) to a
new show LiveView that renders the full record alongside a Leaflet
map centered on the marker. Owners get a Delete button there as well.
Adds a Maidenhead grid input to the rover-location form. Typing a grid
fills in lat/lon (using square center); editing lat/lon recomputes the
grid at 6-char precision. The phx-change `_target` decides direction so
edits never clobber what the user just typed.
