fix: 加固安全输入边界并修复订阅兼容性 (#3084)

* fix: harden scoped API inputs and isolate login throttling

* fix: close script path gaps and harden security boundaries

* fix: preserve subscription aliases and avoid extension eval

* fix: allow cancelling invalid historical subscriptions

* fix: make script parent validation explicit for CodeQL

* fix: limit command execution and clarify trusted path branches

* fix: separate diff tool script access from config APIs

* fix: clean up obsolete subscription SSH credentials

back/shared/shellQuote.ts

@@ -0,0 +1,5 @@
+/** Quote one literal POSIX shell argument, including quotes and substitutions. */
+export function shellQuote(value: string): string {
+  if (value.includes('\0')) throw new Error('Invalid shell argument');
+  return "'" + value.replace(/'/g, "'\\''") + "'";
+}