backup: Phase 6 search and export fixes before cleanup

- Added search button to main page header with Ctrl+K listener
- Implemented SearchModal component rendering
- Fixed SearchModal to use axiosInstance with correct backend URL (8916)
- Fixed token key from 'auth_token' to 'inventory_token'
- Verified export endpoints working correctly
- All Phase 6 UAT fixes in place

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

.servers.pid

@@ -1 +1 @@
-{"backend": 782437, "frontend": 782438, "caddy": 782439, "timestamp": 1776929439.3616884}
+{"backend": 799387, "frontend": 799388, "caddy": 799389, "timestamp": 1776932266.0922172}