fix(broker,api): pin real ws version, drop @turbostarter/ai from packages/api

- apps/broker: ws 8.19.1 (didn't exist) → 8.20.0 (latest)
- packages/api: drop dangling @turbostarter/ai workspace ref (same
  prune debt as apps/web)
- pnpm-lock.yaml regenerated from 27 workspaces, 2476 resolved packages

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/api/package.json

@@ -21,7 +21,6 @@
     "@ai-sdk/openai": "2.0.68",
     "@anthropic-ai/sdk": "0.71.2",
     "@hono/zod-validator": "0.7.4",
-    "@turbostarter/ai": "workspace:*",
     "@turbostarter/auth": "workspace:*",
     "@turbostarter/billing": "workspace:*",
     "@turbostarter/db": "workspace:*",