Two critical correctness bugs from recent commits:
1. Hermes Slack signingSecret was stripped from config.yaml on save but
never written to SLACK_SIGNING_SECRET in ~/.hermes/.env, causing data
loss and broken HTTP webhook mode after any channel save.
2. Tauri write_openclaw_config syncs providers to agents/*/models.json
(Issue #127 fix) but the dev-api web shim did not, leaving Gateway
with stale models.json after Models page saves in browser mode.
Add regression tests for both paths.
Co-authored-by: 晴天 <1186258278@users.noreply.github.com>
