feat(volume-browser): phase 2 - file browser UI

- Browse route: /projects/{id}/volumes/{volId}/browse
- Directory listing with file icons, sizes, dates
- Breadcrumb navigation, click-to-navigate directories
- Download entire volume or folder as ZIP
- Upload files via file picker
- i18n EN/RU for all browser strings

web/src/lib/i18n/en.json

@@ -144,6 +144,22 @@
     "updateFailed": "Failed to update volume",
     "deleteFailed": "Failed to delete volume"
   },
+  "volumeBrowser": {
+    "title": "Volume Browser",
+    "loadFailed": "Failed to load directory",
+    "empty": "This directory is empty.",
+    "name": "Name",
+    "size": "Size",
+    "modified": "Modified",
+    "downloadAll": "Download volume as ZIP",
+    "downloadFolder": "Download folder as ZIP",
+    "upload": "Upload files",
+    "uploaded": "Uploaded",
+    "files": "file(s)",
+    "uploadFailed": "Failed to upload files",
+    "browse": "Browse",
+    "download": "Download"
+  },
   "quickDeploy": {
     "title": "Quick Deploy",
     "description": "Deploy a container image with zero configuration. Paste an image URL, review the defaults, and deploy.",