c0re: chmod 0666 mcp.sock after bind so in-container agent user can connect (#658 fixup)

hive-c0re/src/agent_server.rs

@@ -29,6 +29,15 @@ pub fn start(agent: &str, socket_path: &Path, coord: Arc<Coordinator>) -> Result
     }
     let listener = UnixListener::bind(socket_path)
         .with_context(|| format!("bind agent socket {}", socket_path.display()))?;
+    // The socket is bind-mounted into exactly one container as
+    // `/run/hive/mcp.sock` (`lifecycle::set_nspawn_flags`); post-#658
+    // the in-container harness connects as the per-agent unix user,
+    // not root, so the default `tokio::net::UnixListener::bind` perms
+    // (0755) lock it out. 0666 lets the agent user connect; the bind
+    // source dir is per-agent on host so blast radius is unchanged.
+    use std::os::unix::fs::PermissionsExt as _;
+    std::fs::set_permissions(socket_path, std::fs::Permissions::from_mode(0o666))
+        .with_context(|| format!("chmod agent socket {}", socket_path.display()))?;
     tracing::info!(%agent, socket = %socket_path.display(), "agent socket listening");
 
     let path = socket_path.to_path_buf();

hive-c0re/src/manager_server.rs

@@ -23,6 +23,11 @@ pub fn start(coord: Arc<Coordinator>) -> Result<()> {
     }
     let listener = UnixListener::bind(&socket)
         .with_context(|| format!("bind manager socket {}", socket.display()))?;
+    // 0666 so the in-container hm1nd user (post-#658) can connect;
+    // the bind source dir is manager-only on host. See agent_server.rs.
+    use std::os::unix::fs::PermissionsExt as _;
+    std::fs::set_permissions(&socket, std::fs::Permissions::from_mode(0o666))
+        .with_context(|| format!("chmod manager socket {}", socket.display()))?;
     tracing::info!(socket = %socket.display(), "manager socket listening");
 
     tokio::spawn(async move {