feat: user-scoped history/delete/rollback, dashboard & login UI, ignore *.pem

- Filter history/rollback/delete by user_id in secrets-core
- MCP tools/web pass user context; dashboard refresh; favicon static
- .gitignore *.pem; vscode tasks tweaks
- clippy: collapse else-if in rollback latest-history branch

Made-with: Cursor

.gitignore

@@ -4,3 +4,4 @@
 .cursor/
 # Google OAuth 下载的 JSON 凭据文件
 client_secret_*.apps.googleusercontent.com.json
+*.pem