feat(web): integrate Claude LLM streaming with markdown rendering

- Add Anthropic SDK with DeepSeek-compatible API config
- Streaming tool-use loop in WebSocket chat handler
- GitHub-style markdown rendering with markdown-it
- Tool status indicators and thinking states in chat UI
- Fix Tailwind content path and CSS border utility

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/package.json

@@ -10,12 +10,14 @@
     "db:init": "tsx server/db/schema.ts"
   },
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.95.0",
     "better-sqlite3": "^11.6.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.0",
     "cors": "^2.8.5",
     "express": "^4.21.0",
     "lucide-react": "^0.460.0",
+    "markdown-it": "^14.1.1",
     "react": "^18.3.0",
     "react-dom": "^18.3.0",
     "tailwind-merge": "^2.6.0",
@@ -27,6 +29,7 @@
     "@types/better-sqlite3": "^7.6.0",
     "@types/cors": "^2.8.0",
     "@types/express": "^5.0.0",
+    "@types/markdown-it": "^14.1.2",
     "@types/react": "^18.3.0",
     "@types/react-dom": "^18.3.0",
     "@types/ws": "^8.5.0",