feat: add certificate management security and cleanup dialog

- Documented certificate management security features in security.md, including backup and recovery processes.
- Implemented CertificateCleanupDialog component for confirming deletion of orphaned certificates when deleting proxy hosts.
- Enhanced ProxyHosts page to check for orphaned certificates and prompt users accordingly during deletion.
- Added tests for certificate cleanup prompts and behaviors in ProxyHosts, ensuring correct handling of unique, shared, and production certificates.

.vscode/settings.json

@@ -8,7 +8,6 @@
     ]
     ,
     "gopls": {
-        "buildFlags": ["-tags=ignore", "-mod=mod"],
         "env": {
             "GOWORK": "off",
             "GOFLAGS": "-mod=mod",
@@ -17,8 +16,7 @@
         "directoryFilters": [
             "-**/pkg/mod/**",
             "-**/go/pkg/mod/**",
-            "-**/root/go/pkg/mod/**",
-            "-**/golang.org/toolchain@**"
+            "-**/root/go/pkg/mod/**"
         ]
     },
     "go.buildFlags": ["-tags=ignore", "-mod=mod"],