refactor(rbac): migrate API permission checks to resource:action format

Replace all legacy dotted permission codes (vms.view, proxmox.manage, ...)
in PermissionChecker/has_permission across app/api with the new
resource:action format (vm:view, server:manage, ...), per LEGACY_PERMISSION_MAP.
All 33 codes used by the API are now registered in the permission registry.

Also switch the /api/auth/me admin branch to get_all_permissions_v2 so the
endpoint emits permissions in the new format only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/api/dashboard.py

@@ -14,7 +14,7 @@ router = APIRouter()
 @router.get("/api/dashboard/alerts")
 def get_dashboard_alerts(
     db: Session = Depends(get_db),
-    current_user: User = Depends(PermissionChecker("logs.view"))
+    current_user: User = Depends(PermissionChecker("log:view"))
 ):
     """Вернуть события error/critical за последние 24 ч для дашборда"""
     since_24h = utcnow() - timedelta(hours=24)