feat(pskr): enqueue hrrr_fetch_tasks for cells missing HRRR data

The CalibrationSampler joined PSKR midpoints against hrrr_profiles via
nearest-within-window, but post-Phase-3 Stream C nothing bulk-populates
the grid — hrrr_profiles only sees per-QSO point fetches from the Rust
hrrr-point-worker. Result: 0 / 16,042 prod samples had HRRR data.

Producer pattern: when a cell has no profile in the lookahead window,
enqueue a row into hrrr_fetch_tasks at the cell's HRRR-grid-rounded
midpoint. The Rust worker drains it; the next 5-min rolling-window
pass UPSERTs the same sample with non-NULL weather fields. Idempotent
with the existing on-conflict design — no extra worker, no churn on
cells already covered, multiple bands sharing a midpoint dedupe to a
single fetch via Enum.uniq + jsonb point-union in HrrrPointEnqueuer.

lib/microwaveprop/pskr/calibration_sampler.ex

@@ -31,6 +31,8 @@ defmodule Microwaveprop.Pskr.CalibrationSampler do
   alias Microwaveprop.Pskr.SpotHourly
   alias Microwaveprop.Repo
   alias Microwaveprop.SpaceWeather
+  alias Microwaveprop.Weather
+  alias Microwaveprop.Weather.HrrrPointEnqueuer
   alias Microwaveprop.Weather.HrrrProfile
 
   require Logger
@@ -58,12 +60,18 @@ defmodule Microwaveprop.Pskr.CalibrationSampler do
     else
       hrrr_index = build_hrrr_index(hour_utc)
       kp = fetch_kp(hour_utc)
+      cells = bucket_by_cell(spots)
 
-      samples =
-        spots
-        |> bucket_by_cell()
-        |> Enum.map(&build_sample(&1, hour_utc, hrrr_index, kp))
+      # Producer side of the two-pass HRRR join: any cell whose
+      # midpoint has no profile in the lookahead window gets a
+      # `hrrr_fetch_tasks` row enqueued for the Rust hrrr-point-worker
+      # to drain. The next rolling-window cron pass (every 5 min) will
+      # find the landed profile and UPSERT the sample with non-NULL
+      # weather fields. Existing cells with HRRR data already in
+      # memory are skipped — no churn against the queue table.
+      enqueue_missing_hrrr(cells, hour_utc, hrrr_index)
 
+      samples = Enum.map(cells, &build_sample(&1, hour_utc, hrrr_index, kp))
       upsert(samples)
     end
   end
@@ -134,6 +142,37 @@ defmodule Microwaveprop.Pskr.CalibrationSampler do
     end
   end
 
+  # ── HRRR fetch enqueue (producer side) ──────────────────────────
+
+  # For every PSKR cell that has no HRRR profile in the lookahead
+  # window, queue a point fetch at the cell midpoint. Dedup on
+  # `(rounded_hrrr_lat, rounded_hrrr_lon)` so multiple bands sharing
+  # a midpoint enqueue once, and let `HrrrPointEnqueuer.enqueue/1`
+  # union the points into the existing `hrrr_fetch_tasks` row for
+  # this hour rather than racing to insert duplicates.
+  defp enqueue_missing_hrrr(cells, hour_utc, hrrr_index) do
+    points =
+      cells
+      |> Enum.flat_map(fn {{_band, lat, lon}, _spots} ->
+        if nearest_hrrr(lat, lon, hrrr_index) do
+          []
+        else
+          [Weather.round_to_hrrr_grid(lat, lon)]
+        end
+      end)
+      |> Enum.uniq()
+
+    case points do
+      [] ->
+        :ok
+
+      pts ->
+        {:ok, _} = HrrrPointEnqueuer.enqueue(%{hour_utc => pts})
+
+        Logger.info("Pskr.CalibrationSampler: enqueued #{length(pts)} HRRR points for #{hour_utc}")
+    end
+  end
+
   # ── Kp lookup ───────────────────────────────────────────────────
 
   # Single Kp value applies cluster-wide for the hour. We prefer the

test/microwaveprop/pskr/calibration_sampler_test.exs

@@ -1,6 +1,8 @@
 defmodule Microwaveprop.Pskr.CalibrationSamplerTest do
   use Microwaveprop.DataCase, async: true
 
+  import Ecto.Query
+
   alias Microwaveprop.Pskr.CalibrationSample
   alias Microwaveprop.Pskr.CalibrationSampler
   alias Microwaveprop.Pskr.SpotHourly
@@ -133,6 +135,45 @@ defmodule Microwaveprop.Pskr.CalibrationSamplerTest do
       assert sample.hrrr_ducting_detected == nil
     end
 
+    test "enqueues an hrrr_fetch_tasks row when a cell has no nearby HRRR profile" do
+      insert_spot!(%{midpoint_lat: 33.0, midpoint_lon: -97.0})
+
+      assert CalibrationSampler.build_for_hour(@hour) == 1
+
+      [task] =
+        Repo.all(from(t in "hrrr_fetch_tasks", select: %{points: t.points, status: t.status, valid_time: t.valid_time}))
+
+      assert task.status == "queued"
+      assert task.valid_time == DateTime.to_naive(@hour)
+      # The cell midpoint, snapped to HRRR grid (0.01° rounding).
+      assert task.points == [%{"lat" => 33.0, "lon" => -97.0}]
+    end
+
+    test "does not enqueue an hrrr_fetch_tasks row when an HRRR profile already covers the cell" do
+      insert_spot!(%{})
+      insert_hrrr!(%{lat: 33.0, lon: -97.0})
+
+      CalibrationSampler.build_for_hour(@hour)
+
+      assert Repo.aggregate(from(t in "hrrr_fetch_tasks"), :count) == 0
+    end
+
+    test "deduplicates HRRR enqueue points across bands sharing a midpoint" do
+      insert_spot!(%{band: "10000", midpoint_lat: 33.0, midpoint_lon: -97.0})
+      insert_spot!(%{band: "24000", midpoint_lat: 33.0, midpoint_lon: -97.0, sender_grid: "EM13"})
+      insert_spot!(%{band: "10000", midpoint_lat: 35.0, midpoint_lon: -97.0, sender_grid: "EM15"})
+
+      CalibrationSampler.build_for_hour(@hour)
+
+      [task] = Repo.all(from(t in "hrrr_fetch_tasks", select: %{points: t.points}))
+      # Two unique midpoints (33.0,-97.0) and (35.0,-97.0); the second band at the
+      # first midpoint must collapse, otherwise the Rust worker double-fetches the
+      # same lat/lon for one valid_time.
+      assert length(task.points) == 2
+      sorted = Enum.sort_by(task.points, & &1["lat"])
+      assert sorted == [%{"lat" => 33.0, "lon" => -97.0}, %{"lat" => 35.0, "lon" => -97.0}]
+    end
+
     test "stamps the latest Kp from SpaceWeather on every sample in the hour" do
       insert_spot!(%{})
       insert_hrrr!(%{lat: 33.0, lon: -97.0})