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-proto/src/lib.rs

@@ -4,7 +4,7 @@ use bytes::Bytes;
 use lanspread_db::db::{Game, GameFileDescription};
 use serde::{Deserialize, Serialize};
 
-pub const PROTOCOL_VERSION: u32 = 5;
+pub const PROTOCOL_VERSION: u32 = 6;
 
 pub use lanspread_db::db::Availability;
 
@@ -27,6 +27,7 @@ pub struct Hello {
     pub listen_addr: SocketAddr,
     pub library: LibrarySnapshot,
     pub features: Vec<String>,
+    pub call_to_play_events: Vec<CallToPlayEvent>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
@@ -36,6 +37,40 @@ pub struct HelloAck {
     pub listen_addr: SocketAddr,
     pub library: LibrarySnapshot,
     pub features: Vec<String>,
+    pub call_to_play_events: Vec<CallToPlayEvent>,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub struct CallToPlayEvent {
+    pub id: String,
+    pub call_id: String,
+    pub actor: String,
+    pub at: i64,
+    pub action: CallToPlayAction,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub enum CallToPlayAction {
+    Create {
+        game_id: String,
+        max_players: u16,
+        scheduled_for: Option<i64>,
+        deadline: i64,
+    },
+    Respond {
+        ready_at: Option<i64>,
+    },
+    Rsvp,
+    SendMessage {
+        message_id: String,
+        text: String,
+    },
+    Leave,
+    Cancel,
+    Start,
+    AddTime {
+        deadline: i64,
+    },
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
@@ -75,6 +110,9 @@ pub enum Request {
         peer_id: String,
         delta: LibraryDelta,
     },
+    CallToPlayEvents {
+        events: Vec<CallToPlayEvent>,
+    },
     Goodbye {
         peer_id: String,
     },