Offline Work mode + Reconcile Offline Work dialog, menu tooltips, spinner fix; v0.3.0

- Explicit Work Offline toggle (P4V-style): stops server polling, calm offline banner, persisted
- Reconcile Offline Work dialog: preview adds/edits/deletes with per-file checkboxes, opens picked into a changelist
- Make writable (offline edit) context action; backend p4_reconcile_preview/apply + p4_set_writable
- Tooltips (title) on every top-menu item, 5 languages
- Fix .ldr spinner rendering (inline-block + box-sizing) so it's a clean circle everywhere

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "exbyte-depot",
   "private": true,
-  "version": "0.2.4",
+  "version": "0.3.0",
   "type": "module",
   "scripts": {
     "dev": "vite",