feat: account management overhaul + 7 issue resolutions (#147)

- Add smart JSON export/import with schema validation and deduplication
- Add per-account proxy configurations (Issue #79)
- Add advanced account sorting engine (Issues #126 & #99)
- Add compact horizontal layout, AI credits, inline model visibility (Issues #145 & #134)
- Add desktop push notifications for low quota (Issue #53)
- Fix Arch Linux AUR process detection bug (Issue #117)
- Default theme set to Dark Mode (it's better)
- UI Polishing: Improved sort dropdown and symmetrical dialog layouts
- Dev Mode: Resolved port conflicts and single-instance locks
- Updated README and README.zh-CN with new features

src/server/modules/proxy/clients/upstream-error.ts

@@ -15,9 +15,23 @@ export class UpstreamRequestError extends Error {
   }) {
     super(params.message);
     this.name = 'UpstreamRequestError';
+
+    if (params.status && typeof params.status !== 'number') {
+      throw new TypeError('status must be a number');
+    }
+    if (params.headers && typeof params.headers !== 'object') {
+      throw new TypeError('headers must be an object');
+    }
+
     this.status = params.status;
     this.headers = params.headers;
-    this.body = params.body;
+
+    // Sanitize and limit body size
+    if (typeof params.body === 'string') {
+      const sanitized = params.body.replace(/<[^>]*>?/gm, '');
+      this.body = sanitized.substring(0, 1000);
+    } else {
+      this.body = undefined;
+    }
   }
 }
-