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/loginThrottle.ts

@@ -0,0 +1,47 @@
+const RETRY_TTL = 15 * 60 * 1000;
+const MAX_SOURCES = 10000;
+const MAX_RETRY_SECONDS = 5 * 60;
+
+/** Source-specific, bounded backoff; persisted account history is not a lock. */
+export class LoginThrottle {
+  private sources = new Map<
+    string,
+    { failures: number; lastFailure: number }
+  >();
+
+  private get(source: string, now: number) {
+    const state = this.sources.get(source);
+    if (state && now - state.lastFailure >= RETRY_TTL) {
+      this.sources.delete(source);
+      return undefined;
+    }
+    return state;
+  }
+
+  retryAfter(source: string, now: number): number {
+    const state = this.get(source, now);
+    if (!state || state.failures < 3) return 0;
+    const seconds = Math.min(3 ** state.failures, MAX_RETRY_SECONDS);
+    return Math.max(
+      0,
+      Math.ceil((seconds * 1000 - (now - state.lastFailure)) / 1000),
+    );
+  }
+
+  fail(source: string, now: number): number {
+    const failures = Math.min((this.get(source, now)?.failures || 0) + 1, 6);
+    this.sources.delete(source);
+    if (this.sources.size >= MAX_SOURCES) {
+      this.sources.delete(this.sources.keys().next().value!);
+    }
+    this.sources.set(source, { failures, lastFailure: now });
+    return failures;
+  }
+
+  reset(source: string) {
+    this.sources.delete(source);
+  }
+  clear() {
+    this.sources.clear();
+  }
+}