fix: use inputSchema instead of parameters for AI SDK v6 tool

Changed debug logging to access inputSchema property which exists on AI SDK v6 tools,
instead of parameters which doesn't exist. This fixes the TypeScript build error.

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

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

apps/playground/src/app/api/chat/route.ts

@@ -56,7 +56,7 @@ export async function POST(request: NextRequest) {
     // Debug: Check the search tool structure
     console.log('🔍 Search tool structure:', {
       description: searchTpmjsToolsTool.description,
-      parameters: typeof searchTpmjsToolsTool.parameters,
+      inputSchema: typeof searchTpmjsToolsTool.inputSchema,
       execute: typeof searchTpmjsToolsTool.execute,
     });