fix: show session friendly name in resume message and status bar

/history/{session_id} now returns a 'name' field alongside messages.
resumeSession() uses data.name first, then the sessionNames map, then
raw ID as fallback — so named sessions display correctly even on page
load before the sessions panel has been opened.

'Resumed session X' message also now shows the friendly name.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/session_store.py

@@ -73,6 +73,17 @@ def save(session_id: str, messages: list[dict]) -> None:
     path.write_text(json.dumps(data, indent=2))
 
 
+def get_name(session_id: str) -> str:
+    """Return the friendly name for a session, or '' if none set."""
+    path = _path(session_id)
+    if not path.exists():
+        return ""
+    try:
+        return json.loads(path.read_text()).get("name", "")
+    except Exception:
+        return ""
+
+
 def rename(session_id: str, name: str) -> bool:
     """Set (or clear) the friendly name on a session. Returns False if not found."""
     path = _path(session_id)