Stream bodymap image file through authenticated endpoint.

This endpoint serves bodymap diagram images with proper authentication via the API-key middleware. The public contract uses an exercise ID plus validated query parameters; internal filenames remain server-owned. Each image request counts as an API call.

Bodymaps are an exercise feature: routines and workouts have no bodymap image of their own.

Args: exercise_id: Exercise ID. gender: Gender variant, either male or female. theme: Image theme, either light or dark. view: Body view, either front or back. settings: Application settings injected via dependency.

Returns: FileResponse with the image file.

Raises: HTTPException: 403 if tier is not allowed. HTTPException: 404 if exercise or bodymap image file is not found.

Example: GET /stream/images/bodymaps/1?gender=male&theme=light&view=front