video_analyze_tool's local-path branch read raw bytes via
_detect_video_mime_type (extension-only, no magic-byte check) with no
call to agent.file_safety.raise_if_read_blocked, unlike the image-gen
and video-gen provider plugins that already route local inputs through
that shared chokepoint (#57698). A model could point video_url at a
credential store (e.g. .env, auth.json) renamed or symlinked to a
video-like extension and have its raw bytes base64-encoded and sent to
the vision provider.
vision_analyze_tool and its native fast path (_vision_analyze_native)
had the same gap in their local-file branches; they were only
incidentally protected by the image magic-byte sniff rejecting
non-image content, not by the intended read guard.
Add raise_if_read_blocked() to all three local-file branches, mirroring
the existing plugins/image_gen and plugins/video_gen call sites.