fix: warn when /sessions falls back to live-only list (v0.3.3)

Phone showed 2 sessions because apiProxy catalog failed (pre-0.3.2 inject bug) and live-agent fallback hid cold Web sessions. Surface that mode explicitly.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/catalog.test.ts

@@ -8,6 +8,7 @@ import {
 
 test('visible sessions exclude archived blank and subagent', () => {
   const catalog: CatalogSnapshot = {
+    complete: true,
     archivedIds: new Set(['arch']),
     sessionsById: new Map([
       ['ok', { sessionId: 'ok', title: 'OK', blank: false, running: true, updatedAt: 1 }],