feat(session): ✨ add detached session mode

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

bin/rclaude

@@ -1522,6 +1522,15 @@ if is_local "$host"; then
         exit 1
     fi
     sync_tmux_conf local
+    # RCLAUDE_DETACHED=1 → spawn the tmux session in the background and
+    # return the session name on stdout. Used by supervisor processes
+    # (e.g. `clare web`) that want to bring up a Claude session without
+    # attaching the current terminal.
+    if [ -n "${RCLAUDE_DETACHED:-}" ]; then
+        tmux new-session -d -s "$session" "$(build_inner "$dir")"
+        printf '%s\n' "$session"
+        exit 0
+    fi
     exec tmux new-session -s "$session" "$(build_inner "$dir")"
 fi