feat(webgpu): add actionable UI error message for enabling chrome webgpu flags

webgpu_prototype.html

@@ -55,8 +55,13 @@
                 statusEl.textContent = '[Status] Model loaded successfully!';
                 btnEl.disabled = false;
             } catch (err) {
-                statusEl.textContent = '[Status] Error loading model: ' + err.message;
+                if (err.message.includes('GPU adapter') || err.message.includes('webgpu')) {
+                    statusEl.innerHTML = '<span style="color: red;">[Status] WebGPU disabled by browser. To fix this, open a new tab and go to <b>chrome://flags/#enable-unsafe-webgpu</b>, set it to "Enabled", and restart your browser.</span>';
+                } else {
+                    statusEl.textContent = '[Status] Error loading model: ' + err.message;
+                }
                 console.error(err);
+                btnEl.disabled = false;
                 return;
             }
         }