feat: Serverless Functions as AI Tools (#16919)

## Summary

This PR enables serverless functions to be exposed as AI tools, allowing
them to be used by AI agents.

### Changes

- Added new `SERVERLESS_FUNCTION` tool category
- Added `toolDescription`, `toolInputSchema`, and `toolOutputSchema`
fields to serverless functions
- Created database migration for the new schema columns
- Added tool index query and resolver for fetching available tools
- Added Settings AI page tabs (Skills, Tools, Settings) with new tools
table
- Added utility to convert tool schema to JSON schema format
- Updated frontend to display tools in the settings page

### Implementation Details

- Serverless functions can now define tool metadata (description,
input/output schemas)
- These functions are automatically registered in the tool registry
- The tool index endpoint allows querying available tools with their
schemas
- Settings page now has a dedicated Tools tab showing all available
tools

packages/twenty-server/src/engine/core-modules/application/application-sync.service.ts

@@ -703,6 +703,8 @@ export class ApplicationSyncService {
           timeoutSeconds: serverlessFunctionToSync.timeoutSeconds,
           handlerPath: serverlessFunctionToSync.handlerPath,
           handlerName: serverlessFunctionToSync.handlerName,
+          toolInputSchema: serverlessFunctionToSync.toolInputSchema,
+          isTool: serverlessFunctionToSync.isTool,
         },
       };
 
@@ -747,6 +749,8 @@ export class ApplicationSyncService {
         handlerName: serverlessFunctionToCreate.handlerName,
         applicationId,
         serverlessFunctionLayerId,
+        toolInputSchema: serverlessFunctionToCreate.toolInputSchema,
+        isTool: serverlessFunctionToCreate.isTool,
       };
 
       const createdServerlessFunction =