notify: only "the app is gone" deletes a device row

reported from the field on the first real push: it failed with BadDeviceToken
and the server deleted the registration. the build was production-signed and
the row said sandbox — a configuration mismatch, with the device and the app
both perfectly fine.

pruning there destroys the evidence. the phone re-registers on next launch,
the row comes back looking healthy, and the next send fails identically; you
can lose a day to that loop without ever seeing what is actually wrong.

so the one set becomes three. Unregistered/UNREGISTERED/NOT_FOUND prune —
apple and google are saying the app is uninstalled. BadDeviceToken,
DeviceTokenNotForTopic, TopicDisallowed, INVALID_ARGUMENT and
SENDER_ID_MISMATCH are OURS: the row is kept and the log says what to check.
everything else is transient and still counts toward three strikes.

INVALID_ARGUMENT was the sharpest one. it is how fcm reports a malformed
MESSAGE — including a non-string in `data`, which is the mistake this codebase
is most likely to make and already has a test for. deleting on it meant one
bug in the payload builder would wipe every android device from the registry
on a single send, presenting as "android push stopped working" with nothing
left to explain why.

misconfigured is also not counted as a strike. not deleting is not enough on
its own — a persistent mismatch would reach three failures and delete the row
anyway, which is the same bug with a slower fuse.

the apns log now names the mismatch rather than the reason code, since the
code alone sends people to look at the device: it prints the row's environment
and topic and says to check the SHIPPED artefact rather than the intermediate
build, which is exactly where this one hid.

src/servers/sidecar-registry.ts

@@ -428,6 +428,17 @@ export function onClaudeMessage(handler: (sessionKey: string, msg: TurnMessage,
   });
 }
 
+// See `PersistentSession.notify` in claude-manager.ts — a separate, non-durable ping, not part of the
+// transcript the message above relays.
+export function onClaudeNotify(
+  handler: (sessionKey: string, userId: number, kind: 'turn-ended' | 'input-needed') => void,
+): () => void {
+  return on('claude:notify', (ev) => {
+    if (ev.type !== 'claude:notify') return;
+    handler(ev.sessionKey, ev.userId, ev.kind);
+  });
+}
+
 // ── OpenCode Code (single sidecar, handling 'opencode') ──
 
 export async function spawnOpenCodeStreaming(params: OpenCodeRunParams): Promise<void> {