fix(api-docs): resolve no-useless-escape lint errors

- endpoints.js: replace `\"` with `\\"` in xray response example so the
  rendered docs actually show escaped JSON-in-JSON (the original
  single-quoted `\"` collapsed to a bare `"` and produced malformed output).
- CodeBlock.vue: drop the unnecessary `\[` inside the regex character
  class `[{}\[\]]`; `[` does not need escaping inside `[...]`.

frontend/src/pages/api-docs/CodeBlock.vue

@@ -17,7 +17,7 @@ function escapeHtml(str) {
 function highlightJson(str) {
   const escaped = escapeHtml(str);
   return escaped.replace(
-    /("(?:[^"\\]|\\.)*")\s*(:)|("(?:[^"\\]|\\.)*")|(-?\d+\.?\d*(?:[eE][+-]?\d+)?)\b|(true|false)|(null)|([{}\[\]])/g,
+    /("(?:[^"\\]|\\.)*")\s*(:)|("(?:[^"\\]|\\.)*")|(-?\d+\.?\d*(?:[eE][+-]?\d+)?)\b|(true|false)|(null)|([{}[\]])/g,
     (_m, key, colon, string, number, bool, nil) => {
       if (colon) return `<span class="json-key">${key}</span>${colon}`;
       if (string) return `<span class="json-string">${string}</span>`;

frontend/src/pages/api-docs/endpoints.js

@@ -704,7 +704,7 @@ export const sections = [
         method: 'POST',
         path: '/panel/xray/',
         summary: 'Return the Xray config template (JSON string), available inbound tags, client reverse tags, and the configured outbound test URL in one response.',
-        response: '{\n  "success": true,\n  "obj": {\n    "xraySetting": "{...raw xray config...}",\n    "inboundTags": "[\"inbound-443\"]",\n    "clientReverseTags": "[]",\n    "outboundTestUrl": "https://www.google.com/generate_204"\n  }\n}',
+        response: '{\n  "success": true,\n  "obj": {\n    "xraySetting": "{...raw xray config...}",\n    "inboundTags": "[\\"inbound-443\\"]",\n    "clientReverseTags": "[]",\n    "outboundTestUrl": "https://www.google.com/generate_204"\n  }\n}',
       },
       {
         method: 'GET',