docs: update HANDOFF.md — #4 done, next is #1r secret-args badge

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

HANDOFF.md

@@ -75,12 +75,21 @@ evidence, proposed fixes, and acceptance criteria.
 
 ## Current state (as of this handoff)
 
-- 58 tests in `tests/`, ruff clean, CI = lint + pytest (py3.10/3.12) on push/PR.
+- **56 tests** in `tests/test_core.py`, ruff clean, CI = lint + pytest (py3.10/3.12).
+- `main` = `13d6b91` (PR #15 merged). No unpushed commits.
+- **Completed items:** #2 (spawn-test, PR #11), #3 (backup restore UI, PR #14),
+  #4 (stale-file protection, PR #15).
+- **Next item:** #1r — secret-in-args warning badge (remainder of item 1).
+  `is_secret_key` / `_is_secret_value` / `redact_args` already in `bcc_core.py`.
+  Scope: a non-blocking warning badge when a secret-shaped value sits in `args`
+  instead of `env` (safer pattern). See issue #1 on Gitea for acceptance criteria.
 - Recent features you should know exist: lenient JSON repair
   (`repair_json_text`, `parse_pasted_json_verbose`, `repair_config_file` +
   RepairDialog), ArgsEdit numbered gutter + `split_suspicious_args`,
   resizable splitters with QSettings persistence, secret masking, Claude Code
   profile at `~/.claude.json` (settings.json only as "legacy" when it holds
-  parked servers).
+  parked servers), backup restore UI (RestoreDialog, `list_backups`,
+  `backup_diff`, `restore_backup`), stale-file protection (StaleDialog,
+  `config_mtime`, `external_change_summary`).
 - GUI can't be smoke-tested in CI; note in each PR whether you ran
   `python bcc.py` locally and what you checked.