ci: Add proper SQL migration runner with tracking

- Creates run-migrations.ts that reads migrations/*.sql files
- Tracks applied migrations in schema_migrations table by filename
- Handles existing version-based schema by adding filename column
- CI now runs migrations before deploy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.woodpecker/.ci.yml

@@ -148,7 +148,7 @@ steps:
     commands:
       - cd backend
       - npm ci --prefer-offline
-      - npx tsx src/db/migrate.ts
+      - npx tsx src/db/run-migrations.ts
     depends_on:
       - docker-backend
     when: