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>

public/app.html

@@ -14,7 +14,8 @@
     <p style="color:var(--muted);max-width:420px;margin:10px auto">This app shows YOUR live dashboard — payments, team, coaching. To prove a position is yours, link it once with your wallet (a free signature, it can't move funds):</p>
     <p style="color:var(--muted);max-width:420px;margin:10px auto;text-align:left">1. Open <b>rmcircle.team/my</b> in your browser<br>2. Enter your member ID → <b>Messages</b> → sign in with your wallet<br>3. Tap <b>“Connect Telegram”</b> — it deep-links right back to this bot</p>
     <p style="margin:18px 0 8px"><button id="btn-open-site" class="btn btn-primary">Open the dashboard to link ↗</button></p>
-    <p><button id="btn-browse" class="btn">Just looking? See how the team works</button></p>
+    <p><button id="btn-join" class="btn btn-primary" style="background:linear-gradient(135deg,var(--gold),var(--gold2))">Not a member yet? Join the team</button></p>
+    <p><button id="btn-browse" class="btn">Just looking? See how it works</button></p>
   </div>
   <div id="st-error" style="display:none">
     <h1 style="font-size:22px">Hmm, that didn't verify</h1>