feat(call-to-play)!: coordinate game sessions across peers

Implement the launcher design as a production peer-to-peer feature. Call to
Play actions are immutable, validated events broadcast over the existing QUIC
control channel, deduplicated in a bounded in-memory history, and exchanged in
Hello/HelloAck so late joiners reconstruct current calls.

Add the Tauri bridge and modular launcher surfaces for play-now and scheduled
calls, check-in, readiness buffers, role-aware controls, chat, tickers, and
actual caller launch. A deterministic frontend reducer derives presentation
state from replicated history. Extend the JSONL peer harness with publish/list
commands and a three-peer live-delivery and late-join scenario.

This intentionally raises the only supported wire protocol from version 5 to
version 6; older builds are not supported. Document the transport architecture
and exclude generated peer-test state from Docker build contexts.

Test Plan:
- `just fmt` -- passed
- `just clippy` -- passed
- `just test` -- passed
- `just frontend-test` -- passed, 20 tests
- `just build` -- passed
- `just peer-cli-tests S2 S48` -- passed
- `git diff --cached --check` -- passed

crates/lanspread-peer/src/context.rs

@@ -10,6 +10,7 @@ use crate::{
     PeerEvent,
     StreamInstallProvider,
     Unpacker,
+    call_to_play::CallToPlayStore,
     events,
     library::LocalLibraryState,
     peer_db::PeerGameDB,
@@ -51,6 +52,7 @@ pub struct Ctx {
     pub shutdown: CancellationToken,
     pub task_tracker: TaskTracker,
     pub active_outbound_transfers: OutboundTransfers,
+    pub call_to_play: Arc<RwLock<CallToPlayStore>>,
 }
 
 /// Context for peer connection handling.
@@ -69,6 +71,7 @@ pub struct PeerCtx {
     pub shutdown: CancellationToken,
     pub task_tracker: TaskTracker,
     pub active_outbound_transfers: OutboundTransfers,
+    pub call_to_play: Arc<RwLock<CallToPlayStore>>,
 }
 
 impl std::fmt::Debug for PeerCtx {
@@ -113,6 +116,7 @@ impl Ctx {
             shutdown,
             task_tracker,
             active_outbound_transfers,
+            call_to_play: Arc::new(RwLock::new(CallToPlayStore::default())),
         }
     }
 
@@ -135,6 +139,7 @@ impl Ctx {
             shutdown: self.shutdown.clone(),
             task_tracker: self.task_tracker.clone(),
             active_outbound_transfers: self.active_outbound_transfers.clone(),
+            call_to_play: self.call_to_play.clone(),
         }
     }
 }