supervisor: unique cc-ci-supervisor web-UI name (same invariant as the upgrader)

_archive_stale_titles() generalized to (title, label); launch-supervisor's
spawn_supervisor() archives every older 'cc-ci-supervisor' session before
launching, so exactly one session carries the name. 11 historical supervisor
sessions archive-renamed live ('supervisor archive — <date> <time>').

cc-ci-plan/launch-supervisor.py

@@ -98,6 +98,12 @@ def spawn_supervisor(sid, reason):
     Path(LOG_DIR).mkdir(parents=True, exist_ok=True)
     if _sup_alive():
         _sup_kill(); time.sleep(1)
+    # Unique-name invariant (same as the upgrader): archive-rename every older session titled
+    # SUP_SESSION so the one this launch creates is the ONLY 'cc-ci-supervisor' in the web UI.
+    try:
+        lu._archive_stale_titles(SUP_SESSION, "supervisor archive —")
+    except Exception:
+        pass
     kf = Path(LOG_DIR) / f".kickoff-{SUP_SESSION}.txt"
     kf.write_text(build_kickoff(sid, reason))
     share = "--share" if OPENCODE_SHARE else ""

cc-ci-plan/launch-upgrader.py

@@ -286,19 +286,22 @@ def _db_created_ms(sid):
     except Exception:
         return 0
 
-def _archive_stale_titles():
+def _archive_stale_titles(title=None, label=None):
-    """Rename every existing top-level session titled SESSION to a dated archive title, so
+    """Rename every existing top-level session with the given canonical title to a dated
-    EXACTLY ONE session ever carries the canonical name (the one this launch creates). This
+    archive title, so EXACTLY ONE session ever carries the canonical name (the one the next
-    keeps the run trivially findable in the opencode web UI and makes the title lookup in
+    launch creates). Keeps the run trivially findable in the opencode web UI and makes the
-    _session_id() unambiguous. Old runs stay browsable under 'upgrader archive — weekly <date>'."""
+    title lookup in _session_id() unambiguous. Old runs stay browsable under
+    '<label> — <date>'. Also used by launch-supervisor.py for its own session name."""
+    title = title or SESSION
+    label = label or ("upgrader archive — weekly" if title == "cc-ci-upgrader" else f"{title} archive —")
     rows = _server_get("/session") or []
     rows = rows if isinstance(rows, list) else rows.get("data", [])
     for s in rows:
-        if s.get("title") == SESSION and not (s.get("parentID") or s.get("parentId")):
+        if s.get("title") == title and not (s.get("parentID") or s.get("parentId")):
             created = _db_created_ms(s["id"])
             d = datetime.fromtimestamp(created / 1000).strftime("%Y-%m-%d") if created else "unknown-date"
-            _server_patch(f"/session/{s['id']}", {"title": f"upgrader archive — weekly {d}"})
+            _server_patch(f"/session/{s['id']}", {"title": f"{label} {d}"})
-            log(f"  archived old session {s['id'][:20]} → 'upgrader archive — weekly {d}'")
+            log(f"  archived old session {s['id'][:20]} → '{label} {d}'")
 
 def _session_id():
     """The opencode session this launcher manages. Prefers the pinned id recorded at launch