prepare v0.15 (#544)

* 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

* prepare v0.15

.changeset/v0150-security-hardening.md

@@ -0,0 +1,7 @@
+---
+"agent-browser": minor
+---
+
+- Added security hardening: authentication vault, content boundary markers, domain allowlist, action policy, action confirmation, and output length limits.
+- Added `--download-path` flag (and `AGENT_BROWSER_DOWNLOAD_PATH` env / `downloadPath` config key) to set a default download directory.
+- Added `--selector` flag to `scroll` command for scrolling within specific container elements.