feat: multi-Oracle server support with runtime switching

Complete implementation of multi-server Oracle database support:

Backend:
- Multi-pool Oracle with lazy loading per server
- Email-to-server cache for automatic server discovery
- JWT tokens include server_id claim
- /auth/check-identity and /auth/check-email endpoints
- /auth/my-servers endpoint for listing user's accessible servers
- Server switch with password re-authentication

Frontend:
- New ServerSelector component for header dropdown
- Multi-step login flow (identity → server → password)
- Server switching from header with password modal
- Mobile drawer menu with server selection
- Dark mode support for all new components
- URL bookmark support with ?server= query param

Scripts:
- Unified start.sh replacing start-prod.sh/start-test.sh
- Unified ssh-tunnel.sh with multi-server support
- Updated status.sh for new architecture

Tests:
- E2E tests for multi-server and single-server login flows
- Backend unit tests for all new endpoints
- Oracle multi-pool integration tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/settings.json

@@ -2,5 +2,35 @@
   "statusLine": {
     "type": "command",
     "command": "/home/claude/.claude/statusline.sh"
+  },
+  "permissions": {
+    "allow": [
+      "Bash(npm run dev)",
+      "Bash(npm run build)",
+      "Bash(npm run lint)",
+      "Bash(npm run format)",
+      "Bash(npm run preview)",
+      "Bash(npm run serve)",
+      "Bash(npm run test:e2e*)",
+      "Bash(npm test*)",
+      "Bash(./start.sh*)",
+      "Bash(./start-backend.sh*)",
+      "Bash(./start-frontend.sh*)",
+      "Bash(./status.sh)",
+      "Bash(pytest*)",
+      "Bash(python -m pytest*)",
+      "Bash(ruff check*)",
+      "Bash(ruff format*)",
+      "Bash(mypy*)",
+      "Bash(pip install*)",
+      "Bash(git checkout*)",
+      "Bash(git status)",
+      "Bash(git diff*)",
+      "Bash(git add*)",
+      "Bash(git commit*)",
+      "Bash(git log*)",
+      "Bash(git branch*)",
+      "Bash(agent-browser*)"
+    ]
   }
 }