Fix dictation lifecycle and add real STT e2e

packages/app/src/utils/attempt-guard.ts

@@ -0,0 +1,36 @@
+export class AttemptCancelledError extends Error {
+  constructor(message = "Attempt cancelled") {
+    super(message);
+    this.name = "AttemptCancelledError";
+  }
+}
+
+/**
+ * Tiny helper for async lifecycles:
+ * - Call `next()` to start a new attempt and invalidate previous ones
+ * - Call `cancel()` to invalidate any in-flight attempt
+ * - Call `assertCurrent(id)` after awaits to enforce a single active attempt
+ */
+export class AttemptGuard {
+  private attemptId = 0;
+
+  public next(): number {
+    this.attemptId += 1;
+    return this.attemptId;
+  }
+
+  public cancel(): void {
+    this.attemptId += 1;
+  }
+
+  public isCurrent(id: number): boolean {
+    return id === this.attemptId;
+  }
+
+  public assertCurrent(id: number): void {
+    if (!this.isCurrent(id)) {
+      throw new AttemptCancelledError();
+    }
+  }
+}
+