Update .kiro: remove SQLite hooks, add PostgreSQL migration hook, add workflow steering, sync specs

.kiro/hooks/migration-registration-check.kiro.hook

@@ -0,0 +1,16 @@
+{
+  "enabled": true,
+  "name": "Migration Registration Reminder",
+  "description": "When a new migration file is created in backend/migrations/, reminds the agent to add it to the POSTGRES_MIGRATIONS array in run-all.js so the pipeline will execute it during deploy.",
+  "version": "1",
+  "when": {
+    "type": "fileCreated",
+    "patterns": [
+      "backend/migrations/*.js"
+    ]
+  },
+  "then": {
+    "type": "askAgent",
+    "prompt": "A new migration file was created. If this migration uses the Postgres pool (require('../db')), add its filename to the POSTGRES_MIGRATIONS array in backend/migrations/run-all.js so the CI/CD pipeline will run it automatically during deploy. Skip this if the file is run-all.js itself."
+  }
+}