fix(api): configure Vercel functions for API routes with maxDuration

- Add explicit functions configuration to vercel.json
- Set maxDuration to 60 seconds for all API routes
- This ensures Vercel properly detects and deploys API routes as serverless functions

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

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

apps/web/vercel.json

@@ -1,5 +1,10 @@
 {
   "$schema": "https://openapi.vercel.sh/vercel.json",
   "buildCommand": "cd ../.. && turbo build --filter=@tpmjs/web",
-  "installCommand": "pnpm install"
+  "installCommand": "pnpm install",
+  "functions": {
+    "app/api/**/*.ts": {
+      "maxDuration": 60
+    }
+  }
 }