feat(tests): add comprehensive tests for ProxyHosts and Uptime components

- Introduced isolated coverage tests for ProxyHosts with various scenarios including rendering, bulk apply, and link behavior.
- Enhanced existing ProxyHosts coverage tests to include additional assertions and error handling.
- Added tests for Uptime component to verify rendering and monitoring toggling functionality.
- Created utility functions for setting labels and help texts related to proxy host settings.
- Implemented bulk settings application logic with progress tracking and error handling.
- Added toast utility tests to ensure callback functionality and ID incrementing.
- Improved type safety in test files by using appropriate TypeScript types.

frontend/src/components/ImportSitesModal.tsx

@@ -32,8 +32,9 @@ export default function ImportSitesModal({ visible, onClose, onUploaded }: Props
       setLoading(false)
       if (onUploaded) onUploaded()
       onClose()
-    } catch (err: any) {
-      setError(err?.message || 'Upload failed')
+    } catch (err: unknown) {
+      const msg = err instanceof Error ? err.message : String(err)
+      setError(msg || 'Upload failed')
       setLoading(false)
     }
   }