Trip members viewing another member's shared photo were getting a 404
because the proxy endpoints always used the requesting user's Immich
credentials instead of the photo owner's. The ?userId= query param the
client already sent was silently ignored.
- Add canAccessUserPhoto() to verify the asset is shared and the
requesting user is a trip member before allowing cross-user proxying
- Pass optional ownerUserId through proxyThumbnail, proxyOriginal, and
getAssetInfo so credentials are fetched for the correct user
- Enforce shared=1 check so unshared photos remain inaccessible
d765a80ea3