fix(ui): reset Files navigation state when switching groups

GroupPage keeps the same component instance across a group switch (no
key at the router), so currentPath/selected/filter were leaking from
the group just left. A directory that exists in one group but not the
other (e.g. "outputs") then showed an empty listing after switching.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016SF6RKNBKg9qejmoMJ9ybA

1 files changed, 4 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/app.js b/packages/meshbay-hub/src/meshbay_hub/static/app.js
index 5c2bada..b863460 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/app.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/app.js
@@ -1669,6 +1669,10 @@ function GroupPage({ groupId, group, token, username, userId, userPrefs,
   const defaultTab = (userPrefs && (userPrefs[`default_tab:${groupId}`] || userPrefs['default_tab'])) || 'chat';
   const [tab, setTab] = useState(defaultTab);
   useEffect(() => { setTab(defaultTab); }, [groupId]);
+  // A directory from the group just left rarely exists in the one just
+  // entered (e.g. "outputs" in one group, absent in another) — Files would
+  // otherwise show that stale path and list nothing.
+  useEffect(() => { setCurrentPath(''); setSelected(new Set()); setFilter(''); }, [groupId]);
   const [groupMuted, setGroupMuted] = useState(() => !!(group && group.muted));
 
   const _lastTouch = useRef(0);