feat(browser): add persistent Camofox sessions and VNC URL discovery (salvage #4400) (#4419)

Adds two Camofox features:

1. Persistent browser sessions: new `browser.camofox.managed_persistence`
   config option. When enabled, Hermes sends a deterministic profile-scoped
   userId to Camofox so the server maps it to a persistent browser profile
   directory. Cookies, logins, and browser state survive across restarts.
   Default remains ephemeral (random userId per session).

2. VNC URL discovery: Camofox /health endpoint returns vncPort when running
   in headed mode. Hermes constructs the VNC URL and includes it in navigate
   responses so the agent can share it with users.

Also fixes camofox_vision bug where call_llm response object was passed
directly to json.dumps instead of extracting .choices[0].message.content.

Changes from original PR:
- Removed browser_evaluate tool (separate feature, needs own PR)
- Removed snapshot truncation limit change (unrelated)
- Config.yaml only for managed_persistence (no env var, no version bump)
- Rewrote tests to use config mock instead of env var
- Reverted package-lock.json churn

Co-authored-by: analista <psikonetik@gmail.com.com>

website/docs/user-guide/configuration.md

@@ -1016,6 +1016,8 @@ browser:
   inactivity_timeout: 120        # Seconds before auto-closing idle sessions
   command_timeout: 30             # Timeout in seconds for browser commands (screenshot, navigate, etc.)
   record_sessions: false         # Auto-record browser sessions as WebM videos to ~/.hermes/browser_recordings/
+  camofox:
+    managed_persistence: false   # When true, Camofox sessions persist cookies/logins across restarts
 ```
 
 The browser toolset supports multiple providers. See the [Browser feature page](/docs/user-guide/features/browser) for details on Browserbase, Browser Use, and local Chrome CDP setup.