The inbound-media validator _is_allowed_bridge_path() checked against
IMAGE_CACHE_DIR / AUDIO_CACHE_DIR / VIDEO_CACHE_DIR / DOCUMENT_CACHE_DIR
value-imported at module load. After the base.py cache-dir getters became
per-call resolvers, the bridge writes media into the active profile's cache
while the validator still matched the frozen launch-profile constants — so
media was rejected under a profile override (multi-profile gateway).
Resolve the cache roots per-call via the get_*_cache_dir() getters and drop
the now-unused frozen value-imports. Caught by automated review on #55867.