feat: hand parser uses 'x' blanks instead of guessing suits/cards

Per Brian: never invent. Unknown suit -> 'x' (e.g. "Ax","Kx","4x"); fully
unknown card -> "x". "AA, ace of spades" -> ["As","Ax"]; "AK on A4x" -> board
["Ax","4x","x"]. Each card's suit is independent (a hole 'As' doesn't make a
board ace 'As'). Viewer renders 'x' as a muted unknown card and 'Rx' as the rank
with a neutral suit dot.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyra/web/static/hand.html

@@ -37,6 +37,8 @@
     .card .r{font-size:1rem;}
     .card.red{color:#c8102e;}
     .card.back{background:#2a3550;color:#2a3550;}
+    .card.unknown{background:#2a3550;color:#7c879e;font-size:1.2rem;}
+    .card .nosuit{color:#9aa3b5;}
 
     .seat{position:absolute;transform:translate(-50%,-50%);width:96px;text-align:center;
       background:rgba(13,16,22,.85);border:1px solid var(--border);border-radius:10px;padding:5px 4px;}
@@ -84,9 +86,12 @@
 
     function cardEl(code, sm){
       if(!code) return '';
-      const m = String(code).trim().match(/^(10|[2-9TJQKA])\s*([shdc])$/i);
-      if(!m) return `<span class="card${sm?' sm':''}">${esc(code)}</span>`;
+      const c = String(code).trim();
+      if(c.toLowerCase()==='x') return `<span class="card${sm?' sm':''} unknown">?</span>`;
+      const m = c.match(/^(10|[2-9TJQKA])\s*([shdcx])$/i);
+      if(!m) return `<span class="card${sm?' sm':''}">${esc(c)}</span>`;
       const r = m[1].toUpperCase().replace('10','T'); const s = m[2].toLowerCase();
+      if(s==='x') return `<span class="card${sm?' sm':''}"><span class="r">${r}</span><span class="nosuit">·</span></span>`;
       return `<span class="card${sm?' sm':''}${RED.has(s)?' red':''}"><span class="r">${r}</span><span>${SUIT[s]}</span></span>`;
     }
     const cards = (arr, sm) => (arr||[]).map(c=>cardEl(c,sm)).join('');