refactor: migrate to monorepo structure with Docker, PocketBase, and e2e tests

- Reorganize into apps/, packages/, docs/, e2e/, pocketbase/ directories
- Add Dockerfiles for web, worker, and PocketBase services
- Add docker-compose.yml for local orchestration
- Add turbo.json for monorepo task management
- Add Playwright e2e test infrastructure
- Add PocketBase backend with migrations
- Remove Vite/Next.js/ESLint/PostCSS config files
- Update package.json with workspace dependencies
- Add .env.example and .dockerignore

apps/web/app/api/notes/[id]/backlinks/route.ts

@@ -0,0 +1,18 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { withAuth } from '@/lib/auth';
+import { getBacklinks } from '@/lib/services/note-service';
+
+type RouteContext = { params: Promise<{ id: string }> };
+
+// GET /api/notes/[id]/backlinks — Get notes that link to this note
+export const GET = withAuth<RouteContext>(
+  async (request: NextRequest, _user, context) => {
+    const { id } = await context!.params;
+    const backlinks = await getBacklinks(id);
+
+    return NextResponse.json({
+      items: backlinks,
+      totalItems: backlinks.length,
+    });
+  }
+);