fix(call-to-play): compact expired snapshots

Expired call histories were removed on the next store insertion, so an otherwise
idle peer could continue carrying stale payload through handshakes after the
five-minute UI retention ended.

Run the same inactive-call compaction before local and handshake snapshots. This
makes the expiry boundary exact without trimming any event from an active call.

Test Plan:
- `just fmt` -- passed
- `just clippy` -- passed
- `just test` -- passed, 147 peer tests
- `git diff --cached --check` -- passed

crates/lanspread-peer/src/services/handshake.rs

@@ -67,7 +67,7 @@ pub(super) async fn build_hello_ack(ctx: &PeerCtx) -> eyre::Result<HelloAck> {
         let library_guard = ctx.local_library.read().await;
         build_library_snapshot(&library_guard)
     };
-    let call_to_play_events = ctx.call_to_play.read().await.snapshot();
+    let call_to_play_events = ctx.call_to_play.write().await.snapshot();
     Ok(HelloAck {
         peer_id: ctx.peer_id.as_ref().clone(),
         proto_ver: PROTOCOL_VERSION,
@@ -84,7 +84,7 @@ async fn build_hello_from_state(ctx: &HandshakeCtx) -> eyre::Result<Hello> {
         let library_guard = ctx.local_library.read().await;
         build_library_snapshot(&library_guard)
     };
-    let call_to_play_events = ctx.call_to_play.read().await.snapshot();
+    let call_to_play_events = ctx.call_to_play.write().await.snapshot();
     Ok(Hello {
         peer_id: ctx.peer_id.as_ref().clone(),
         proto_ver: PROTOCOL_VERSION,
@@ -538,7 +538,7 @@ mod tests {
             .expect("current protocol hello should be accepted");
 
         assert_eq!(
-            ctx.call_to_play.read().await.snapshot(),
+            ctx.call_to_play.write().await.snapshot(),
             [call_to_play_event()]
         );
         assert!(matches!(