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/database/typeorm/core/migrations/common/1767364430164-add-tool-schema-to-serverless-function.ts

@@ -0,0 +1,25 @@
+import { type MigrationInterface, type QueryRunner } from 'typeorm';
+
+export class AddToolSchemaToServerlessFunction1767364430164
+  implements MigrationInterface
+{
+  name = 'AddToolSchemaToServerlessFunction1767364430164';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."serverlessFunction" ADD "toolInputSchema" jsonb`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "core"."serverlessFunction" ADD "isTool" boolean NOT NULL DEFAULT false`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "core"."serverlessFunction" DROP COLUMN "isTool"`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "core"."serverlessFunction" DROP COLUMN "toolInputSchema"`,
+    );
+  }
+}