v1.1.0 — Gzip canvas compression + throttled sends

- Canvas snapshots gzip-compressed before sending: 1MB raw -> ~1-5KB
  for a mostly-white canvas, ~100-500KB for a busy one
- Semaphore throttles concurrent canvas sends (default 20) to prevent
  memory spikes during connection bursts
- Frontend decompresses gzip via browser DecompressionStream API
- New config: MAX_CONCURRENT_CANVAS_SENDS (default 20)
- Added flate2 dependency for gzip encoding

Cargo.toml

@@ -24,7 +24,7 @@ default-members = [
 resolver = "2"
 
 [workspace.package]
-version = "1.0.0"
+version = "1.1.0"
 edition = "2024"
 
 [workspace.dependencies]
@@ -37,6 +37,7 @@ config-env = { path = "crates/adapters/config-env" }
 http-axum = { path = "crates/adapters/http-axum" }
 socketio = { path = "crates/adapters/socketio" }
 websocket = { path = "crates/adapters/websocket" }
+flate2 = "1"
 futures = "0.3"
 
 axum = "0.8.9"