feat(schema): add adapter column to events, drop source

Replaces module-path-based source column (e.g. "central/adapters/nws")
with stable adapter identifier (e.g. "nws") that foreign-keys to
config.adapters.name.

Migration 011:
- ADD COLUMN adapter TEXT
- Backfill via REPLACE(source, 'central/adapters/', '')
- SET NOT NULL + FK RESTRICT
- CREATE INDEX (adapter, received DESC) for dashboard queries
- DROP COLUMN source

Code changes:
- Event model: source field renamed to adapter
- All adapters: use adapter="name" instead of source="central/adapters/name"
- Archive: write adapter column instead of source

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sql/migrations/011_events_add_adapter_column.sql

@@ -0,0 +1,46 @@
+-- Migration 011: Add adapter column to events, drop source column
+-- Replaces module-path-based source with stable adapter identifier
+
+-- Add adapter column (idempotent)
+ALTER TABLE public.events ADD COLUMN IF NOT EXISTS adapter TEXT;
+
+-- Backfill from existing source values
+UPDATE public.events
+SET adapter = REPLACE(source, 'central/adapters/', '')
+WHERE adapter IS NULL AND source IS NOT NULL;
+
+-- Make NOT NULL after backfill (idempotent check)
+DO $$
+BEGIN
+    IF EXISTS (
+        SELECT 1 FROM information_schema.columns
+        WHERE table_schema = 'public'
+          AND table_name = 'events'
+          AND column_name = 'adapter'
+          AND is_nullable = 'YES'
+    ) THEN
+        ALTER TABLE public.events ALTER COLUMN adapter SET NOT NULL;
+    END IF;
+END $$;
+
+-- Add FK constraint (idempotent check)
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1 FROM information_schema.table_constraints
+        WHERE constraint_name = 'events_adapter_fkey'
+          AND table_name = 'events'
+    ) THEN
+        ALTER TABLE public.events
+        ADD CONSTRAINT events_adapter_fkey
+        FOREIGN KEY (adapter) REFERENCES config.adapters(name)
+        ON DELETE RESTRICT;
+    END IF;
+END $$;
+
+-- Add index for dashboard queries (idempotent)
+CREATE INDEX IF NOT EXISTS events_adapter_received_idx
+ON public.events (adapter, received DESC);
+
+-- Drop deprecated source column (idempotent)
+ALTER TABLE public.events DROP COLUMN IF EXISTS source;

sql/schema.sql

@@ -1,9 +1,12 @@
 -- Central Data Hub schema
 -- PostgreSQL 16 + TimescaleDB + PostGIS
+-- NOTE: Migrations in sql/migrations/ are the source of truth.
+-- This file is for reference and initial setup only.
 
 CREATE TABLE IF NOT EXISTS events (
     id              TEXT NOT NULL,                     -- CloudEvent id
-    source          TEXT NOT NULL,                     -- adapter identity
+    adapter         TEXT NOT NULL                      -- adapter identity (FK to config.adapters.name)
+                    REFERENCES config.adapters(name) ON DELETE RESTRICT,
     category        TEXT NOT NULL,                     -- "wx.alert.<type>"
     time            TIMESTAMPTZ NOT NULL,              -- event-time UTC
     expires         TIMESTAMPTZ,
@@ -21,6 +24,9 @@ SELECT create_hypertable('events', 'time', if_not_exists => TRUE);
 CREATE INDEX IF NOT EXISTS events_category_time_idx
     ON events (category, time DESC);
 
+CREATE INDEX IF NOT EXISTS events_adapter_received_idx
+    ON events (adapter, received DESC);
+
 CREATE INDEX IF NOT EXISTS events_geom_gist
     ON events USING GIST (geom);