Polish Foundry desktop UI: billing redesign, sidebar hover menu, org switching fix

- Redesign billing page with task-hours pricing model (Free: 8h, Pro: 200h/seat)
- Add bulk hour purchase packages and Stripe payment management
- Remove Usage nav section, add upgrade CTA in Members for free plan
- Fix gear icon to open menu on hover with debounced timers
- Fix org switching in workspace flyout (portal outside-click detection)
- Fix tab strip padding when sidebar is collapsed
- Update website components and Tauri config

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

foundry/packages/desktop/src-tauri/tauri.conf.json

@@ -4,24 +4,12 @@
   "version": "0.1.0",
   "identifier": "dev.sandboxagent.foundry",
   "build": {
-    "beforeDevCommand": "VITE_DESKTOP=1 pnpm --filter @sandbox-agent/foundry-frontend dev",
+    "beforeDevCommand": "FOUNDRY_FRONTEND_CLIENT_MODE=mock VITE_DESKTOP=1 pnpm --filter @sandbox-agent/foundry-frontend dev",
     "devUrl": "http://localhost:4173",
     "frontendDist": "../frontend-dist"
   },
   "app": {
-    "windows": [
-      {
-        "title": "Foundry",
-        "width": 1280,
-        "height": 800,
-        "minWidth": 900,
-        "minHeight": 600,
-        "resizable": true,
-        "theme": "Dark",
-        "titleBarStyle": "Overlay",
-        "hiddenTitle": true
-      }
-    ],
+    "windows": [],
     "security": {
       "csp": null
     }