feat: technical role can view all applications with search, separate /all route

- Add GET /applications/all endpoint for admin/technical with search by user name/email/ID
- GET /applications now always returns only the current user's apps (fix for technical seeing all apps)
- Technical role can view/edit/delete any application (same as admin)
- Add 'All Applications' page with search bar, user info columns, status badges
- Add 'All Applications' link to admin and technical sidebar navigation
- Add user relation to Application TypeScript interface

frontend/src/types/index.ts

@@ -27,6 +27,7 @@ export interface Application {
   replicas: number;
   port: number;
   userId: string;
+  user?: User;
   clusterId?: string;
   poolId?: string;
   latestImageTag?: string;