Discard Pocket invitation parses after Cancel

docs/specs/pocket-app.md

@@ -20,13 +20,13 @@ Pocket is:
 
 > auth screens + `MobileTerminalUi`/`MobileWall` + **`RemotePtyAdapter`**
 
-— the composition [mobile-terminal-ui.md](./mobile-terminal-ui.md) owns, which the website also wires on `FakePtyAdapter` (`website/src/components/PocketTerminalExperience.tsx`). **Everything outside the PTY core no-ops or is absent** — `getCwd` → null, shells/clipboard empty, alerts inert, `alertAwait` settling `cancelled` rather than never resolving.
+— the composition [mobile-terminal-ui.md](./mobile-terminal-ui.md) owns, also wired on `FakePtyAdapter` (`website/src/components/PocketTerminalExperience.tsx`). **Everything outside the PTY core no-ops or is absent** — `getCwd` → null, shells/clipboard empty, alerts inert, `alertAwait` settling `cancelled` rather than never resolving.
 
 **Scanning is the only way in** — no setup password, no typed credential; the code on the computer's screen is both account setup and pairing.
 
 **A QR the native camera opened is origin bootstrap only.** The `#pair?` fragment is erased before the first render, parsed or not; nothing is retained, no call is made, the token is not spent, and the auth screen asks for a scan from inside Pocket. **An installed iOS Pocket can never receive a scanned hash** — Camera opens Safari, a different partition. (rationale)
 
-**The scanner reads a code as data**: it never navigates, and camera or pasted text goes to `parsePairingInvitationUrl` ([relay.md](./relay.md) owns the grammar) (rationale). **The invitation lives in memory only**, cleared on every terminal outcome.
+**Must parse scanned or pasted text with `parsePairingInvitationUrl`, never navigate** ([relay.md](./relay.md) owns the grammar; rationale). **Must keep invitations in memory only, clearing them on every terminal outcome.** **Must discard parses finishing after Cancel or teardown.**
 
 **After the parse.**
 

lib/src/remote/pocket-app/ScanInvitation.test.tsx

@@ -108,6 +108,36 @@ async function paste(text: string): Promise<void> {
 }
 
 describe('reading a code', () => {
+  it.each([
+    ['camera', 'cancel'], ['camera', 'unmount'], ['paste', 'cancel'], ['paste', 'unmount'],
+  ])('drops a pending %s parse after %s', async (source, ending) => {
+    const camera = fakeCamera();
+    const { onScanned, onCancel } = render({ startScan: camera.startScan });
+    await settle();
+    const { url } = await invitationUrl();
+    if (source === 'paste') act(() => setNativeFieldValue(pasteField(), url));
+    act(() => {
+      if (source === 'camera') camera.read(url);
+      else container.querySelector('form')!.dispatchEvent(new Event('submit', { bubbles: true, cancelable: true }));
+      if (ending === 'cancel') buttonNamed(container, 'Cancel')!.click();
+      else root.render(null);
+    });
+    await settle();
+
+    expect(onScanned).not.toHaveBeenCalled();
+    if (ending === 'cancel') expect(onCancel).toHaveBeenCalledOnce();
+    expect(camera.stops).toBeGreaterThan(0);
+  });
+
+  it('accepts a fresh paste if the caller keeps the scanner after cancellation', async () => {
+    const { onScanned } = render();
+    await settle();
+    act(() => buttonNamed(container, 'Cancel')!.click());
+    const { url } = await invitationUrl();
+    await paste(url);
+    expect(onScanned).toHaveBeenCalledOnce();
+  });
+
   it('hands a camera read straight to the caller, without navigating', async () => {
     const camera = fakeCamera();
     const { onScanned } = render({ startScan: camera.startScan });

lib/src/remote/pocket-app/ScanInvitation.tsx

@@ -141,6 +141,9 @@ export function ScanInvitation({
    * an error on screen telling the user to scan again.
    */
   const acceptingRef = useRef(false);
+  // Retire pending parses without disabling fresh input if this screen stays up.
+  const parseGenerationRef = useRef(0);
+  useEffect(() => () => { parseGenerationRef.current++; }, []);
   /**
    * The tail of every start this screen has run, so **at most one is ever in
    * flight**.
@@ -176,12 +179,15 @@ export function ScanInvitation({
   const accept = useCallback(
     async (text: string): Promise<void> => {
       if (acceptingRef.current) return;
+      const generation = parseGenerationRef.current;
       const invitation = await parsePairingInvitationUrl(text, appOrigin);
+      if (generation !== parseGenerationRef.current || acceptingRef.current) return;
       if (!invitation) {
-        setRejected(await rejectionFor(text, appOrigin));
+        const reason = await rejectionFor(text, appOrigin);
+        if (generation === parseGenerationRef.current && !acceptingRef.current) setRejected(reason);
         return;
       }
-      if (acceptingRef.current) return;
+      parseGenerationRef.current++;
       acceptingRef.current = true;
       // A code that parsed clears the rejection this screen may still be
       // showing: the two rows stack otherwise, and a ceremony that fails after
@@ -261,6 +267,7 @@ export function ScanInvitation({
           className={pkButton({ tone: 'ghost', size: 'sm' })}
           disabled={busy !== null}
           onClick={() => {
+            parseGenerationRef.current++;
             stopCamera();
             onCancel();
           }}