The SSRF protection added in #3041 blocks all private/internal addresses
unconditionally in browser_navigate(). This prevents legitimate local use
cases (localhost apps, LAN devices) when using Camofox or the built-in
headless Chromium without a cloud provider.
The check is only meaningful for cloud backends (Browserbase, BrowserUse)
where the agent could reach internal resources on a remote machine. Local
backends give the user full terminal and network access already — the
SSRF check adds zero security value.
Add _is_local_backend() helper that returns True when Camofox is active
or no cloud provider is configured. Both the pre-navigation and
post-redirect SSRF checks now skip when running locally. The
browser.allow_private_urls config option remains available as an
explicit opt-out for cloud mode.