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.