add security hardening features (#543)

* add security hardening features

- Add authentication vault (`auth save/login/list/show/delete`) so credentials are stored locally and never exposed to the LLM (fixes Snyk W007)
- Add `--content-boundaries` flag to wrap page-sourced output in structural markers, helping LLMs distinguish tool output from untrusted page content (fixes Snyk W011)
- Add `--allowed-domains` flag to restrict browser navigation to trusted domains
- Add `--action-policy` for static allow/deny gating of action categories, with opt-in `--confirm-actions`/`--confirm-interactive` for orchestrator or human-in-the-loop confirmation
- Add `--max-output` flag to truncate large page outputs, preventing context flooding
- New docs page at /security, updated README, SKILL.md, CLI help text, and templates

* fixes

* fixes

* fixes

* fixes

* fixes

* fixes

* fixes

* docs

docs/src/lib/docs-navigation.ts

@@ -35,6 +35,7 @@ export const navigation: NavSection[] = [
       { name: "Streaming", href: "/streaming" },
       { name: "Profiler", href: "/profiler" },
       { name: "iOS Simulator", href: "/ios" },
+      { name: "Security", href: "/security" },
     ],
   },
   {