docs: vendor the documentation site into the monorepo

Fold the standalone 3x-ui-docs project (Next.js 16 + Fumadocs, deployed to
docs.sanaei.dev) into docs/ so the panel and its documentation share a single
source of truth, the way sing-box keeps its docs in-tree. The old repo becomes
redundant and can be retired.

- Import the full site under docs/ (app, components, content, lib, public,
  scripts, config). The self-contained pnpm project sits alongside the existing
  engineering notes with no filename collisions.
- Re-point "Edit on GitHub" links from MHSanaei/3x-ui-docs to this repo's
  docs/content/docs path (docs/lib/shared.ts, docs/app/.../page.tsx).
- Add docs-ci.yml and docs-deploy.yml under .github/workflows/, scoped to
  docs/** and run with working-directory: docs, since GitHub only runs
  workflows from the repo-root .github/. deploy-static.yml's GitHub Pages
  publish (CNAME docs.sanaei.dev) carries over unchanged.

Follow-up (outside this commit): attach the docs.sanaei.dev custom domain to
this repository's Pages (or set the Vercel project's root directory to docs),
confirm the site is live from the monorepo, then delete MHSanaei/3x-ui-docs.

docs/lib/xray/api-client.test.ts

@@ -0,0 +1,67 @@
+import { describe, it, expect } from 'vitest';
+import { normalizeBase, joinUrl, buildCurl, buildFetchSnippet } from './api-client';
+
+describe('normalizeBase', () => {
+  it('strips a trailing slash', () => {
+    expect(normalizeBase('https://panel.example.com:2053/')).toBe('https://panel.example.com:2053');
+  });
+
+  it('leaves a clean base unchanged', () => {
+    expect(normalizeBase('https://panel.example.com:2053')).toBe('https://panel.example.com:2053');
+  });
+});
+
+describe('joinUrl', () => {
+  it('joins with exactly one slash regardless of input slashes', () => {
+    expect(joinUrl('https://x.com/', 'panel/api/inbounds/list')).toBe(
+      'https://x.com/panel/api/inbounds/list',
+    );
+    expect(joinUrl('https://x.com', '/panel/api/inbounds/list')).toBe(
+      'https://x.com/panel/api/inbounds/list',
+    );
+  });
+});
+
+const base = {
+  baseUrl: 'https://panel.example.com:2053',
+  token: 'TKN',
+  path: '/panel/api/inbounds/list',
+};
+
+describe('buildCurl', () => {
+  it('GET emits the Bearer header, a single-quoted URL, and no body flag', () => {
+    const cmd = buildCurl({ ...base, method: 'GET' });
+    expect(cmd).toContain("-X GET");
+    expect(cmd).toContain("-H 'Authorization: Bearer TKN'");
+    expect(cmd).toContain("'https://panel.example.com:2053/panel/api/inbounds/list'");
+    expect(cmd).not.toContain('--data');
+    expect(cmd).not.toContain('-d ');
+  });
+
+  it('POST with a body emits --data and a JSON content type', () => {
+    const cmd = buildCurl({ ...base, method: 'POST', path: '/panel/api/inbounds/add', body: '{"up":0}' });
+    expect(cmd).toContain('-X POST');
+    expect(cmd).toContain("--data '{\"up\":0}'");
+    expect(cmd).toContain("Content-Type: application/json");
+  });
+
+  it('POST without a body omits --data', () => {
+    const cmd = buildCurl({ ...base, method: 'POST', path: '/panel/api/inbounds/resetAllTraffics' });
+    expect(cmd).not.toContain('--data');
+  });
+});
+
+describe('buildFetchSnippet', () => {
+  it('GET sets method + Authorization and no body', () => {
+    const snip = buildFetchSnippet({ ...base, method: 'GET' });
+    expect(snip).toContain("method: 'GET'");
+    expect(snip).toContain("'Authorization': 'Bearer TKN'");
+    expect(snip).not.toContain('body:');
+  });
+
+  it('POST with a body includes a JSON.stringify body', () => {
+    const snip = buildFetchSnippet({ ...base, method: 'POST', path: '/panel/api/inbounds/add', body: '{"up":0}' });
+    expect(snip).toContain("method: 'POST'");
+    expect(snip).toContain('body: JSON.stringify(');
+  });
+});