fix(api): remove redundant CsrfGuard from FederationController

CsrfGuard is already applied globally via APP_GUARD in AppModule.
The explicit @UseGuards(CsrfGuard) on FederationController caused a
DI error because CsrfService is not provided in FederationModule.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/federation/federation.controller.ts

@@ -14,7 +14,6 @@ import { getDefaultWorkspaceId } from "./federation.config";
 import { AuthGuard } from "../auth/guards/auth.guard";
 import { AdminGuard } from "../auth/guards/admin.guard";
 import { WorkspaceGuard } from "../common/guards/workspace.guard";
-import { CsrfGuard } from "../common/guards/csrf.guard";
 import { SkipCsrf } from "../common/decorators/skip-csrf.decorator";
 import type { PublicInstanceIdentity } from "./types/instance.types";
 import type { ConnectionDetails } from "./types/connection.types";
@@ -29,7 +28,6 @@ import {
 import { FederationConnectionStatus } from "@prisma/client";
 
 @Controller("api/v1/federation")
-@UseGuards(CsrfGuard)
 export class FederationController {
   private readonly logger = new Logger(FederationController.name);