Using init: true in docker

docker/docker-compose.yml

@@ -108,6 +108,11 @@ services:
       retries: 3
       start_period: 10s
 
+    # Use tini as PID 1 to reap zombie child processes.
+    # Without this, grandchild processes (esbuild, cargo, etc.) spawned by
+    # npm/cargo during worktree setup and gate checks become zombies.
+    init: true
+
     # Restart policy – restart on crash but not on manual stop
     restart: unless-stopped