feat(secrets-mcp): /changelog 页（Markdown 渲染）、首页与 Dashboard 入口

- 新增 CHANGELOG.md 构建嵌入、pulldown-cmark 渲染、路由 /changelog
- 首页页脚与 MCP Dashboard 页脚提供变更记录链接；同步 README、AGENTS
- 版本 secrets-mcp 0.5.24

crates/secrets-mcp/templates/dashboard.html

@@ -57,6 +57,8 @@
             font-family: 'JetBrains Mono', monospace;
             margin-top: auto;
         }
+        .app-footer a { color: var(--accent); text-decoration: none; }
+        .app-footer a:hover { text-decoration: underline; }
         .card { background: #111827; border: 1px solid rgba(240,246,252,0.08); border-radius: 18px;
                 padding: 20px; width: 100%; }
         .card-title { font-size: 22px; font-weight: 700; margin-bottom: 24px; color: #fff; }
@@ -288,7 +290,7 @@
         </div>
     </div>
 </div>
-<footer class="app-footer">{{ version }}</footer>
+<footer class="app-footer">{{ version }} · <a href="/changelog" data-i18n="changelogLink">变更记录</a></footer>
 </div><!-- /main -->
 </div><!-- /content-shell -->
 </div><!-- /layout -->
@@ -379,6 +381,7 @@ const T = {
         regenFailed: '重置失败，请刷新页面重试。',
         ariaShowPw: '显示密码',
         ariaHidePw: '隐藏密码',
+        changelogLink: '变更记录',
     },
     'zh-TW': {
         navMcp: 'MCP', navEntries: '條目', navTrash: '回收站', navAudit: '審計',
@@ -417,6 +420,7 @@ const T = {
         regenFailed: '重置失敗，請重新整理頁面再試。',
         ariaShowPw: '顯示密碼',
         ariaHidePw: '隱藏密碼',
+        changelogLink: '變更記錄',
     },
     'en': {
         navMcp: 'MCP', navEntries: 'Entries', navTrash: 'Trash', navAudit: 'Audit',
@@ -455,6 +459,7 @@ const T = {
         regenFailed: 'Reset failed. Please refresh and try again.',
         ariaShowPw: 'Show password',
         ariaHidePw: 'Hide password',
+        changelogLink: 'Changelog',
     }
 };