feat(web): add workspace management UI (M2 #12)

- Create workspace listing page at /settings/workspaces
  - List all user workspaces with role badges
  - Create new workspace functionality
  - Display member count per workspace

- Create workspace detail page at /settings/workspaces/[id]
  - Workspace settings (name, ID, created date)
  - Member management with role editing
  - Invite member functionality
  - Delete workspace (owner only)

- Add workspace components:
  - WorkspaceCard: Display workspace info with role badge
  - WorkspaceSettings: Edit workspace settings and delete
  - MemberList: Display and manage workspace members
  - InviteMember: Send invitations with role selection

- Add WorkspaceMemberWithUser type to shared package
- Follow existing app patterns for styling and structure
- Use mock data (ready for API integration)

apps/api/src/users/preferences.controller.ts

@@ -0,0 +1,55 @@
+import {
+  Controller,
+  Get,
+  Put,
+  Body,
+  UseGuards,
+  Request,
+  UnauthorizedException,
+} from "@nestjs/common";
+import { PreferencesService } from "./preferences.service";
+import { UpdatePreferencesDto } from "./dto";
+import { AuthGuard } from "../auth/guards/auth.guard";
+
+/**
+ * Controller for user preferences endpoints
+ * All endpoints require authentication
+ */
+@Controller("users/me/preferences")
+@UseGuards(AuthGuard)
+export class PreferencesController {
+  constructor(private readonly preferencesService: PreferencesService) {}
+
+  /**
+   * GET /api/users/me/preferences
+   * Get current user's preferences
+   */
+  @Get()
+  async getPreferences(@Request() req: any) {
+    const userId = req.user?.id;
+
+    if (!userId) {
+      throw new UnauthorizedException("Authentication required");
+    }
+
+    return this.preferencesService.getPreferences(userId);
+  }
+
+  /**
+   * PUT /api/users/me/preferences
+   * Update current user's preferences
+   */
+  @Put()
+  async updatePreferences(
+    @Body() updatePreferencesDto: UpdatePreferencesDto,
+    @Request() req: any
+  ) {
+    const userId = req.user?.id;
+
+    if (!userId) {
+      throw new UnauthorizedException("Authentication required");
+    }
+
+    return this.preferencesService.updatePreferences(userId, updatePreferencesDto);
+  }
+}