✨ feat(admin): add user data dashboard for cross-project data visualization

Add comprehensive admin dashboard to view and manage user data across all projects:

Backend:
- Add admin endpoints to Chat, Todo, Contacts, Calendar, Picture, Zitare, Presi
- Each backend exposes GET/DELETE /api/v1/admin/user-data/:userId
- Service-to-service auth via X-Service-Key header

Aggregation (mana-core-auth):
- GET /api/v1/admin/users - Paginated user list with search
- GET /api/v1/admin/users/:userId/data - Aggregated data from all backends
- DELETE /api/v1/admin/users/:userId/data - GDPR deletion across all projects

Frontend (ManaCore web):
- New User Data tab in admin navigation
- User search page at /admin/user-data
- User detail page with ProjectDataCard components
- GDPR deletion dialog with email confirmation

Presi:
- Migrate user_id from UUID to TEXT for Better Auth compatibility
- Add SQL migration script

apps/presi/apps/backend/src/admin/admin.controller.ts

@@ -0,0 +1,46 @@
+import {
+	Controller,
+	Get,
+	Delete,
+	Param,
+	UseGuards,
+	Logger,
+	HttpCode,
+	HttpStatus,
+} from '@nestjs/common';
+import { AdminService } from './admin.service';
+import { ServiceAuthGuard } from './guards/service-auth.guard';
+import { UserDataResponse, DeleteUserDataResponse } from './dto/user-data-response.dto';
+
+/**
+ * Admin controller for cross-service user data management
+ * All endpoints require service key authentication (X-Service-Key header)
+ */
+@Controller('api/v1/admin')
+@UseGuards(ServiceAuthGuard)
+export class AdminController {
+	private readonly logger = new Logger(AdminController.name);
+
+	constructor(private readonly adminService: AdminService) {}
+
+	/**
+	 * Get user data summary for this backend
+	 * Called by mana-core-auth admin service to aggregate cross-project data
+	 */
+	@Get('user-data/:userId')
+	async getUserData(@Param('userId') userId: string): Promise<UserDataResponse> {
+		this.logger.log(`Admin request: getUserData for userId=${userId}`);
+		return this.adminService.getUserData(userId);
+	}
+
+	/**
+	 * Delete all user data from this backend (GDPR right to be forgotten)
+	 * Called by mana-core-auth admin service during cross-project deletion
+	 */
+	@Delete('user-data/:userId')
+	@HttpCode(HttpStatus.OK)
+	async deleteUserData(@Param('userId') userId: string): Promise<DeleteUserDataResponse> {
+		this.logger.log(`Admin request: deleteUserData for userId=${userId}`);
+		return this.adminService.deleteUserData(userId);
+	}
+}

apps/presi/apps/backend/src/admin/admin.module.ts

@@ -0,0 +1,12 @@
+import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { AdminController } from './admin.controller';
+import { AdminService } from './admin.service';
+import { ServiceAuthGuard } from './guards/service-auth.guard';
+
+@Module({
+	imports: [ConfigModule],
+	controllers: [AdminController],
+	providers: [AdminService, ServiceAuthGuard],
+})
+export class AdminModule {}

apps/presi/apps/backend/src/admin/admin.service.ts

@@ -0,0 +1,126 @@
+import { Injectable, Logger, Inject } from '@nestjs/common';
+import { eq, sql, desc, inArray } from 'drizzle-orm';
+import { DATABASE_CONNECTION } from '../db/database.module';
+import type { Database } from '../db/connection';
+import * as schema from '../db/schema';
+import {
+	UserDataResponse,
+	DeleteUserDataResponse,
+	EntityCount,
+} from './dto/user-data-response.dto';
+
+@Injectable()
+export class AdminService {
+	private readonly logger = new Logger(AdminService.name);
+
+	constructor(
+		@Inject(DATABASE_CONNECTION)
+		private readonly db: Database
+	) {}
+
+	async getUserData(userId: string): Promise<UserDataResponse> {
+		this.logger.log(`Getting user data for userId: ${userId}`);
+
+		// Count decks
+		const decksResult = await this.db
+			.select({ count: sql<number>`count(*)::int` })
+			.from(schema.decks)
+			.where(eq(schema.decks.userId, userId));
+		const decksCount = decksResult[0]?.count ?? 0;
+
+		// Count slides (through decks)
+		const userDecks = await this.db
+			.select({ id: schema.decks.id })
+			.from(schema.decks)
+			.where(eq(schema.decks.userId, userId));
+
+		let slidesCount = 0;
+		if (userDecks.length > 0) {
+			const deckIds = userDecks.map((d) => d.id);
+			const slidesResult = await this.db
+				.select({ count: sql<number>`count(*)::int` })
+				.from(schema.slides)
+				.where(inArray(schema.slides.deckId, deckIds));
+			slidesCount = slidesResult[0]?.count ?? 0;
+		}
+
+		// Count shared decks (through decks)
+		let sharedDecksCount = 0;
+		if (userDecks.length > 0) {
+			const deckIds = userDecks.map((d) => d.id);
+			const sharedResult = await this.db
+				.select({ count: sql<number>`count(*)::int` })
+				.from(schema.sharedDecks)
+				.where(inArray(schema.sharedDecks.deckId, deckIds));
+			sharedDecksCount = sharedResult[0]?.count ?? 0;
+		}
+
+		// Get last activity
+		const lastDeck = await this.db
+			.select({ updatedAt: schema.decks.updatedAt })
+			.from(schema.decks)
+			.where(eq(schema.decks.userId, userId))
+			.orderBy(desc(schema.decks.updatedAt))
+			.limit(1);
+		const lastActivityAt = lastDeck[0]?.updatedAt?.toISOString();
+
+		const entities: EntityCount[] = [
+			{ entity: 'decks', count: decksCount, label: 'Decks' },
+			{ entity: 'slides', count: slidesCount, label: 'Slides' },
+			{ entity: 'shared_decks', count: sharedDecksCount, label: 'Shared Links' },
+		];
+
+		const totalCount = decksCount + slidesCount + sharedDecksCount;
+
+		return { entities, totalCount, lastActivityAt };
+	}
+
+	async deleteUserData(userId: string): Promise<DeleteUserDataResponse> {
+		this.logger.log(`Deleting user data for userId: ${userId}`);
+
+		const deletedCounts: EntityCount[] = [];
+		let totalDeleted = 0;
+
+		// Get user's decks first
+		const userDecks = await this.db
+			.select({ id: schema.decks.id })
+			.from(schema.decks)
+			.where(eq(schema.decks.userId, userId));
+
+		if (userDecks.length > 0) {
+			const deckIds = userDecks.map((d) => d.id);
+
+			// Delete shared decks
+			const deletedShared = await this.db
+				.delete(schema.sharedDecks)
+				.where(inArray(schema.sharedDecks.deckId, deckIds))
+				.returning();
+			deletedCounts.push({
+				entity: 'shared_decks',
+				count: deletedShared.length,
+				label: 'Shared Links',
+			});
+			totalDeleted += deletedShared.length;
+
+			// Delete slides (cascade should handle this, but let's be explicit)
+			const deletedSlides = await this.db
+				.delete(schema.slides)
+				.where(inArray(schema.slides.deckId, deckIds))
+				.returning();
+			deletedCounts.push({ entity: 'slides', count: deletedSlides.length, label: 'Slides' });
+			totalDeleted += deletedSlides.length;
+		}
+
+		// Delete decks
+		const deletedDecks = await this.db
+			.delete(schema.decks)
+			.where(eq(schema.decks.userId, userId))
+			.returning();
+		deletedCounts.push({ entity: 'decks', count: deletedDecks.length, label: 'Decks' });
+		totalDeleted += deletedDecks.length;
+
+		this.logger.log(`Deleted ${totalDeleted} records for userId: ${userId}`);
+
+		return { success: true, deletedCounts, totalDeleted };
+	}
+}

apps/presi/apps/backend/src/admin/dto/user-data-response.dto.ts

@@ -0,0 +1,17 @@
+export interface EntityCount {
+	entity: string;
+	count: number;
+	label: string;
+}
+
+export interface UserDataResponse {
+	entities: EntityCount[];
+	totalCount: number;
+	lastActivityAt?: string;
+}
+
+export interface DeleteUserDataResponse {
+	success: boolean;
+	deletedCounts: EntityCount[];
+	totalDeleted: number;
+}

apps/presi/apps/backend/src/admin/guards/service-auth.guard.ts

@@ -0,0 +1,40 @@
+import {
+	Injectable,
+	CanActivate,
+	ExecutionContext,
+	UnauthorizedException,
+	Logger,
+} from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { Request } from 'express';
+
+/**
+ * Guard for internal service-to-service authentication using X-Service-Key header
+ * Used by mana-core-auth to query user data across backends
+ */
+@Injectable()
+export class ServiceAuthGuard implements CanActivate {
+	private readonly logger = new Logger(ServiceAuthGuard.name);
+	private readonly serviceKey: string;
+
+	constructor(private readonly configService: ConfigService) {
+		this.serviceKey = this.configService.get<string>('ADMIN_SERVICE_KEY', 'dev-admin-key');
+	}
+
+	canActivate(context: ExecutionContext): boolean {
+		const request = context.switchToHttp().getRequest<Request>();
+		const providedKey = request.headers['x-service-key'] as string;
+
+		if (!providedKey) {
+			this.logger.warn('Missing X-Service-Key header');
+			throw new UnauthorizedException('Missing service key');
+		}
+
+		if (providedKey !== this.serviceKey) {
+			this.logger.warn('Invalid service key provided');
+			throw new UnauthorizedException('Invalid service key');
+		}
+
+		return true;
+	}
+}

apps/presi/apps/backend/src/app.module.ts

@@ -5,6 +5,7 @@ import { DeckModule } from './deck/deck.module';
 import { SlideModule } from './slide/slide.module';
 import { ThemeModule } from './theme/theme.module';
 import { ShareModule } from './share/share.module';
+import { AdminModule } from './admin/admin.module';
 import { HealthModule } from '@manacore/shared-nestjs-health';
 
 @Module({
@@ -18,6 +19,7 @@ import { HealthModule } from '@manacore/shared-nestjs-health';
 		SlideModule,
 		ThemeModule,
 		ShareModule,
+		AdminModule,
 		HealthModule.forRoot({ serviceName: 'presi-backend' }),
 	],
 })

apps/presi/apps/backend/src/db/migrations/0001_user_id_to_text.sql

@@ -0,0 +1,20 @@
+-- Migration: Change user_id from UUID to TEXT
+-- This allows compatibility with Better Auth nanoid-based user IDs
+
+-- Step 1: Add a temporary column with the new type
+ALTER TABLE decks ADD COLUMN user_id_new TEXT;
+
+-- Step 2: Copy and convert existing data (UUID to TEXT)
+UPDATE decks SET user_id_new = user_id::text WHERE user_id IS NOT NULL;
+
+-- Step 3: Drop the old column
+ALTER TABLE decks DROP COLUMN user_id;
+
+-- Step 4: Rename the new column
+ALTER TABLE decks RENAME COLUMN user_id_new TO user_id;
+
+-- Step 5: Add NOT NULL constraint
+ALTER TABLE decks ALTER COLUMN user_id SET NOT NULL;
+
+-- Step 6: Add index for performance
+CREATE INDEX IF NOT EXISTS decks_user_id_idx ON decks(user_id);

apps/presi/apps/backend/src/db/schema/decks.schema.ts

@@ -6,7 +6,7 @@ import { sharedDecks } from './shared-decks.schema';
 
 export const decks = pgTable('decks', {
 	id: uuid('id').primaryKey().defaultRandom(),
-	userId: uuid('user_id').notNull(),
+	userId: text('user_id').notNull(), // TEXT for Better Auth nanoid user IDs
 	title: text('title').notNull(),
 	description: text('description'),
 	themeId: uuid('theme_id').references(() => themes.id),