feat: dynamic database storage size with PVC expansion

- Add dbStorageSize column to Application entity (default: 1Gi)
- Add dbStorageSize to CreateApplicationDto, frontend types
- Use dynamic storage size in K8s deployDatabase instead of hardcoded 5Gi
- Deploy page: storage size selector with +/- buttons (min 1GB, max 100GB)
- Auto-suggest storage based on DB dump file size (3x dump size, min 1GB)
- Show DB storage in Review step
- App detail: Database Storage section with expand button
- GET /applications/:id/db-storage — read current PVC size from K8s
- PATCH /applications/:id/db-storage — expand PVC (only increase, no shrink)
- PVC resize uses JSON patch on K8s API

frontend/src/app/dashboard/apps/[id]/page.tsx

@@ -66,6 +66,8 @@ export default function AppDetailPage() {
     memoryLimit: '',
     replicas: 1,
   });
+  const [dbStorageSize, setDbStorageSize] = useState('1');
+  const [dbStorageLoading, setDbStorageLoading] = useState(false);
 
   const { data: app, isLoading } = useQuery<Application>({
     queryKey: ['application', appId],
@@ -109,6 +111,36 @@ export default function AppDetailPage() {
     queryFn: () => api.get('/clusters/pools/public').then((r) => r.data),
   });
 
+  // Fetch DB storage size
+  const { data: dbStorageData } = useQuery<{ currentSize: string; savedSize: string }>({
+    queryKey: ['db-storage', appId],
+    queryFn: () => api.get(`/applications/${appId}/db-storage`).then((r) => r.data),
+    enabled: !!app && app.databaseType !== 'none',
+  });
+
+  // Sync dbStorageSize state when data loads
+  useEffect(() => {
+    if (dbStorageData?.currentSize) {
+      const sizeNum = parseInt(dbStorageData.currentSize.replace('Gi', ''), 10) || 1;
+      setDbStorageSize(String(sizeNum));
+    }
+  }, [dbStorageData]);
+
+  const resizeDbMutation = useMutation({
+    mutationFn: (size: string) => api.patch(`/applications/${appId}/db-storage`, { size }),
+    onSuccess: (res) => {
+      if (res.data.success) {
+        toast.success(res.data.message || 'Database storage expanded!');
+        queryClient.invalidateQueries({ queryKey: ['db-storage', appId] });
+      } else {
+        toast.error(res.data.message || 'Failed to expand storage');
+      }
+    },
+    onError: (err: any) => {
+      toast.error(err.response?.data?.message || 'Failed to resize database storage');
+    },
+  });
+
   // Sync form when resource data loads
   useEffect(() => {
     if (resourceUsage?.configured) {
@@ -667,6 +699,71 @@ export default function AppDetailPage() {
             </p>
           </div>
 
+          {/* Database Storage Management */}
+          <div className="bg-gray-50 rounded-xl p-4 mb-4">
+            <h3 className="text-sm font-semibold text-gray-700 mb-3">Database Storage</h3>
+            <div className="flex items-center gap-4">
+              <div className="flex-1">
+                <div className="flex items-center gap-2 mb-2">
+                  <span className="text-xs text-gray-500">Current Size:</span>
+                  <span className="text-sm font-semibold text-gray-800">{dbStorageData?.currentSize || app.dbStorageSize || '1Gi'}</span>
+                </div>
+                <div className="flex items-center gap-3">
+                  <div className="flex items-center border border-gray-300 rounded-lg overflow-hidden">
+                    <button
+                      type="button"
+                      onClick={() => {
+                        const current = parseInt(dbStorageSize, 10);
+                        const min = parseInt((dbStorageData?.currentSize || '1Gi').replace('Gi', ''), 10) || 1;
+                        if (current > min + 1) setDbStorageSize(String(current - 1));
+                      }}
+                      className="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 font-bold text-sm transition-colors"
+                    >
+                      −
+                    </button>
+                    <input
+                      type="number"
+                      min={1}
+                      max={100}
+                      value={dbStorageSize}
+                      onChange={(e) => {
+                        const val = Math.max(1, Math.min(100, parseInt(e.target.value, 10) || 1));
+                        setDbStorageSize(String(val));
+                      }}
+                      className="w-14 text-center py-1.5 border-x border-gray-300 text-sm font-semibold focus:outline-none"
+                    />
+                    <button
+                      type="button"
+                      onClick={() => {
+                        const current = parseInt(dbStorageSize, 10);
+                        if (current < 100) setDbStorageSize(String(current + 1));
+                      }}
+                      className="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 font-bold text-sm transition-colors"
+                    >
+                      +
+                    </button>
+                  </div>
+                  <span className="text-sm text-gray-600">GB</span>
+                  <button
+                    type="button"
+                    onClick={() => {
+                      const newSize = `${parseInt(dbStorageSize, 10)}Gi`;
+                      resizeDbMutation.mutate(newSize);
+                    }}
+                    disabled={
+                      resizeDbMutation.isPending ||
+                      parseInt(dbStorageSize, 10) <= (parseInt((dbStorageData?.currentSize || '1Gi').replace('Gi', ''), 10) || 1)
+                    }
+                    className="btn-primary text-xs px-3 py-1.5 disabled:opacity-50"
+                  >
+                    {resizeDbMutation.isPending ? 'Expanding...' : 'Expand'}
+                  </button>
+                </div>
+                <p className="text-xs text-gray-400 mt-1">فقط امکان افزایش حجم وجود دارد (کاهش ممکن نیست)</p>
+              </div>
+            </div>
+          </div>
+
           {/* DB Dump Upload */}
           <h3 className="text-sm font-semibold text-gray-700 mb-3">Restore Database Dump</h3>
           <div