fix: mobile keyboard accessory buttons — split text/Enter, double-tap confirm for clear/compact

- Remove confirm() dialog which dismissed keyboard and broke Enter delivery
- Send command text and Enter as separate requests with 120ms delay so Ink processes them as distinct events
- Add double-tap confirmation for /clear and /compact (amber "Tap again" state, 2s timeout)
- /init sends immediately (non-destructive)
- Refocus terminal after first tap on confirm buttons to keep keyboard open
- Match accessory button font size to toolbar buttons (0.65rem)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/web/public/mobile.css

@@ -504,10 +504,17 @@
     border: 1px solid rgba(255, 255, 255, 0.15);
     border-radius: 6px;
     color: #e5e5e5;
-    font-size: 0.75rem;
+    font-size: 0.65rem;
     font-weight: 500;
     cursor: pointer;
-    transition: background 0.1s;
+    transition: background 0.15s, border-color 0.15s;
+  }
+
+  /* Confirm state — button turns amber and shows "Tap again" */
+  .accessory-btn.confirming {
+    background: #6b4f00;
+    border-color: #b8860b;
+    color: #ffd54f;
   }
 
   .accessory-btn:active {