Batch is_grid_point backfill and reduce HRRR workers to 5

- Split migration backfill into 50k-row batches to avoid container timeout
- Reduce prod HRRR worker concurrency from 10 to 5

config/runtime.exs

@@ -117,7 +117,7 @@ if config_env() == :prod do
 
   # Production Oban: live scoring, polling, and on-demand QSO enrichment (no cron backfill)
   config :microwaveprop, Oban,
-    queues: [propagation: 1, commercial: 2, solar: 1, weather: 10, hrrr: 10, terrain: 5, iemre: 10, backfill_enqueue: 1],
+    queues: [propagation: 1, commercial: 2, solar: 1, weather: 10, hrrr: 5, terrain: 5, iemre: 10, backfill_enqueue: 1],
     plugins: [
       {Oban.Plugins.Pruner, max_age: 3600 * 24},
       {Oban.Plugins.Lifeline, rescue_after: 30 * 60 * 1000},

priv/repo/migrations/20260405001416_add_is_grid_point_to_hrrr_profiles.exs

@@ -6,16 +6,37 @@ defmodule Microwaveprop.Repo.Migrations.AddIsGridPointToHrrrProfiles do
       add :is_grid_point, :boolean, default: false, null: false
     end
 
-    flush()
-
-    execute(
-      "UPDATE hrrr_profiles SET is_grid_point = true WHERE (lat * 1000)::int % 125 = 0 AND (lon * 1000)::int % 125 = 0",
-      "SELECT 1"
-    )
-
     create index(:hrrr_profiles, [:valid_time],
              where: "is_grid_point = true",
              name: :hrrr_profiles_grid_point_valid_time_idx
            )
+
+    # Backfill is_grid_point in batches to avoid long-running single UPDATE
+    flush()
+
+    execute(
+      """
+      DO $$
+      DECLARE
+        batch_size INT := 50000;
+        rows_updated INT := 1;
+      BEGIN
+        WHILE rows_updated > 0 LOOP
+          UPDATE hrrr_profiles
+          SET is_grid_point = true
+          WHERE id IN (
+            SELECT id FROM hrrr_profiles
+            WHERE is_grid_point = false
+              AND (lat * 1000)::int % 125 = 0
+              AND (lon * 1000)::int % 125 = 0
+            LIMIT batch_size
+          );
+          GET DIAGNOSTICS rows_updated = ROW_COUNT;
+          RAISE NOTICE 'Updated % rows', rows_updated;
+        END LOOP;
+      END $$;
+      """,
+      "SELECT 1"
+    )
   end
 end