feat: enhance watchlist workflow

apps/api/migrations/202606240004_watchlist_enhancements.sql

@@ -0,0 +1,21 @@
+ALTER TABLE app.watchlist_items
+    ADD COLUMN IF NOT EXISTS label TEXT NOT NULL DEFAULT 'general',
+    ADD COLUMN IF NOT EXISTS priority TEXT NOT NULL DEFAULT 'medium',
+    ADD COLUMN IF NOT EXISTS trigger_operator TEXT NOT NULL DEFAULT 'lte',
+    ADD COLUMN IF NOT EXISTS trigger_price_psm DOUBLE PRECISION CHECK (trigger_price_psm >= 0),
+    ADD COLUMN IF NOT EXISTS last_reviewed_at TIMESTAMPTZ;
+
+CREATE TABLE IF NOT EXISTS app.watchlist_events (
+    event_id BIGSERIAL PRIMARY KEY,
+    watchlist_item_id BIGINT NOT NULL REFERENCES app.watchlist_items(watchlist_item_id) ON DELETE CASCADE,
+    event_type TEXT NOT NULL,
+    summary TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_watchlist_items_label
+    ON app.watchlist_items(label);
+CREATE INDEX IF NOT EXISTS idx_watchlist_items_priority
+    ON app.watchlist_items(priority);
+CREATE INDEX IF NOT EXISTS idx_watchlist_events_item_created
+    ON app.watchlist_events(watchlist_item_id, created_at DESC);