fix: inject Rybbit tracking on m.tkmind.cn publication pages

Publication routes and share shells were missing the Rybbit tracker, and
bootstrap now reuses the stored MindSpace analytics secret when Rybbit env
secret is absent.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/local-analytics.md

@@ -58,8 +58,14 @@ Generated Page
    MEMIND_RYBBIT_ID_SECRET=<random-local-secret>
    ```
 
+   If `MEMIND_RYBBIT_ID_SECRET` is omitted, Portal bootstrap reuses the
+   MindSpace analytics secret stored in `mindspace_config` (the same value
+   configured below in memind_adm → Analytics 配置).
+
 3. Restart the local Memind server. Full generated HTML pages receive a
-   same-origin `/rybbit/script.js` tracker. The tracker identifies the visitor
+   same-origin `/rybbit/script.js` tracker. Publication routes under
+   `/u/:owner/pages/:slug` and `/MindSpace/:user/public/...` both receive
+   the tracker. The tracker identifies the visitor
    with a stable pseudonymous owner ID, then records engagement events such as
    `page_click`, scroll depth, and dwell time. Initial pageviews come from
    Rybbit's site setting `trackInitialPageView`.