Wallet help: SafePal + any-wallet in-app-browser path (not just MetaMask/Trust)

Mobile users on SafePal/Coinbase/Rabby had no route in — the deep-link help
only offered MetaMask + Trust. Added a wallet-agnostic instruction (open your
wallet app -> Browser/DApp tab -> type the join URL) that works via the
injected provider our EIP-6963 picker already resolves; join-now fills the
sponsor path into the hint. Dashboard no-wallet message made wallet-agnostic
and names SafePal. No guessed SafePal deep-link scheme (unverified).

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

public/my.js

@@ -317,7 +317,7 @@
     const err=document.getElementById('msgAuthErr');
     try{
       const eth=await window.RMCWallet.pick();
-      if(!eth){err.textContent='No wallet found in this browser. On a phone, open this page inside your wallet app\'s browser (MetaMask or Trust).';return;}
+      if(!eth){err.textContent='No wallet found in this browser. On a phone, open your wallet app (SafePal, MetaMask, Trust, Coinbase…), go to its Browser or DApp tab, and type this page\'s address there — your wallet connects automatically.';return;}
       const accs=await eth.request({method:'eth_requestAccounts'});const account=accs[0];
       const ch=await(await fetch('/api/public/msg-challenge',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({address:account})})).json();
       if(!ch.message)throw new Error(ch.error||'Could not start sign-in.');