fix: user workflow deadlock (#677)

apps/web/components/task/use-passthrough-terminal.ts

@@ -71,6 +71,39 @@ function createKeyEventHandler(options: TerminalKeyHandlerOptions) {
   };
 }
 
+/**
+ * Defer WebGL addon loading to the next animation frame so the initial
+ * synchronous work (Terminal + FitAddon + open) stays within the browser's
+ * frame budget.
+ *
+ * Skips WebGL on Firefox: its canvas fingerprinting protection silently
+ * poisons readback data, corrupting the glyph texture atlas.
+ */
+function deferWebGLAddon(refs: Pick<TerminalInitOptions, "xtermRef" | "webglAddonRef">) {
+  const isFirefox = typeof navigator !== "undefined" && /firefox/i.test(navigator.userAgent);
+  if (isFirefox) {
+    log("Skipping WebGL addon on Firefox (canvas fingerprinting protection)");
+    return;
+  }
+  requestAnimationFrame(() => {
+    const term = refs.xtermRef.current;
+    if (!term || refs.webglAddonRef.current) return;
+    try {
+      const webglAddon = new WebglAddon();
+      webglAddon.onContextLoss(() => {
+        log("WebGL context lost");
+        webglAddon.dispose();
+        refs.webglAddonRef.current = null;
+      });
+      term.loadAddon(webglAddon);
+      refs.webglAddonRef.current = webglAddon;
+      log("WebGL addon loaded");
+    } catch (e) {
+      log("WebGL failed, using canvas:", e);
+    }
+  });
+}
+
 function initTerminalInstance(
   termContainer: HTMLDivElement,
   refs: Pick<
@@ -121,26 +154,7 @@ function initTerminalInstance(
   }
   refs.xtermRef.current = terminal;
   refs.fitAddonRef.current = fitAddon;
-  // Defer WebGL addon loading to the next animation frame so the initial
-  // synchronous work (Terminal + FitAddon + open) stays within the browser's
-  // frame budget and avoids "Violation: 'setTimeout' handler took Xms" warnings.
-  requestAnimationFrame(() => {
-    const term = refs.xtermRef.current;
-    if (!term || refs.webglAddonRef.current) return;
-    try {
-      const webglAddon = new WebglAddon();
-      webglAddon.onContextLoss(() => {
-        log("WebGL context lost");
-        webglAddon.dispose();
-        refs.webglAddonRef.current = null;
-      });
-      term.loadAddon(webglAddon);
-      refs.webglAddonRef.current = webglAddon;
-      log("WebGL addon loaded");
-    } catch (e) {
-      log("WebGL failed, using canvas:", e);
-    }
-  });
+  deferWebGLAddon(refs);
   exposeBufferReader(termContainer, terminal);
   const handleResize = () => {
     const rect = termContainer.getBoundingClientRect();