Restore user/group badges on DB-loaded result cards

The card badge only rendered when f.account_name was set, and the
group (role) badge was nested inside that same check. But save_item
never persisted account_name — only account_id (a GUID) and user_role.
Live SSE cards carried account_name so badges showed during a scan;
now that the grid loads finalized scans from the DB, the gap is exposed
and both badges vanish for earlier scans.

- Persist account_name (migration 11 + save_item) so future scans show
  the user badge. Both M365 and Google cards already carry it.
- _accountPill() in results.js drives the group badge off user_role
  alone (shows for legacy rows) and resolves a best-effort user label:
  account_name → S._allUsers (id/email) → email-style account_id → omit.
  Both card layouts share the one helper.

Legacy rows still lack account_name (never captured), but now show the
group badge and a resolved/email user label where possible.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_db.py

@@ -313,3 +313,23 @@ class TestOrphanScanRecovery:
         self._start_unfinished_scan(tmp_db, "orphan-1")
         assert tmp_db.finalize_orphan_scans() == 1
         assert tmp_db.finalize_orphan_scans() == 0
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# account_name persistence (user/group badge data)
+# ─────────────────────────────────────────────────────────────────────────────
+
+class TestAccountNamePersistence:
+
+    def test_account_name_round_trips(self, tmp_db):
+        sid = tmp_db.begin_scan({"sources": ["email"], "user_ids": []})
+        tmp_db.save_item(sid, _make_card(item_id="an-1"))  # account_name="Test User"
+        tmp_db.finish_scan(sid, total_scanned=1)
+
+        row = [r for r in tmp_db.get_open_items() if r["id"] == "an-1"][0]
+        assert row.get("account_name") == "Test User"
+
+    def test_account_name_column_exists(self, tmp_db):
+        cols = [r[1] for r in tmp_db._connect().execute(
+            "PRAGMA table_info(flagged_items)").fetchall()]
+        assert "account_name" in cols