Mini App join funnel: startapp sponsor attribution + wallet-app handoff

- /app decodes startapp=<sponsorId>[_<angle>] -> unlinked visitors land on the
  sponsor squeeze page /join/<ref>?src=miniapp (linked members still go to
  their dashboard); no-invite prospects get a gold Join button -> /join-now
- tg-app.js: sync __rmcInTg flag; external links route out of the webview via
  openLink/openTelegramLink (wallet deep links reach the wallet app reliably)
- join-now.js in the webview leads with the MetaMask/Trust deep links (no
  injected wallet can exist there); ref + src survive into the wallet browser
- tgbot: links command + weekly digest include the t.me/<bot>/<short>?startapp
  Telegram-native invite once config.miniAppShortName is set (new PATCH key)
- Synced chat.js canned answer + AI prompt (prospects can join from the app)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

private/join-now.html

@@ -67,4 +67,4 @@
   <p class="micro" style="text-align:center">No income is guaranteed. Cryptocurrency and smart-contract participation carry risk. Only use funds you can afford to lose.</p>
 </main>
 <footer class="wrap disclaimer">All figures are read live from the RM Circle smart contract on Polygon. Not an earnings guarantee or investment advice. Participation carries risk of loss.<div class="footer-links"><a href="/">Home</a><a href="/training">Training</a><a href="/how-pay-works">How You Get Paid</a><a href="/contract">Contract Security</a><a href="/disclaimer">Disclaimers</a></div></footer>
-<script src="/track.js"></script><script src="/rmc-wallet.js"></script><script src="/join-now.js"></script><script src="/translate.js" defer></script></body></html>
+<script src="/track.js"></script><script src="/tg-app.js"></script><script src="/rmc-wallet.js"></script><script src="/join-now.js"></script><script src="/translate.js" defer></script></body></html>