Merge PR #140 from crawlsys/feat/webgl-renderer-toggle: WebGL renderer toggle in settings

Includes review fixes (per-device setting + sticky-marker semantics); merged locally because the org-owned fork rejects maintainer pushes.

src/web/public/index.html

@@ -1011,6 +1011,13 @@
                   <option value="og">OG Codeman</option>
                 </select>
               </div>
+              <div class="settings-item" id="appSettingsWebglRendererItem" title="Use the GPU-accelerated WebGL terminal renderer (desktop only). Turn off to force the DOM renderer if you hit GPU glitches. Codeman also auto-falls-back to the DOM renderer after repeated GPU stalls.">
+                <span class="settings-item-label">WebGL Renderer</span>
+                <label class="switch switch-sm">
+                  <input type="checkbox" id="appSettingsWebglRenderer">
+                  <span class="slider"></span>
+                </label>
+              </div>
               <!-- Input Section -->
               <div class="settings-section-header">Input</div>
               <div class="settings-item settings-item-multiline" title="Shows typed characters instantly via overlay while forwarding keystrokes to the server in the background. Enables Tab completion, preserves input across tab switches, and protects against session crashes. Recommended for mobile and high-latency connections.">