The streaming worker path now splices image embeddings on prefill,
closing the silent text-only degrade for `stream=true` image requests.
`inference_stream` gains the same vision-routing block as the
non-streaming `chat_completion`: detect `image_url` content, reject it
against text-only models with `VisionUnsupported` (before any SSE frame
is sent), preprocess each image and expand its `<|image_pad|>` sentinel
to the per-image patch count, then carry the payload through dispatch.
Rather than duplicate the 75-line `route_token!` reasoning/tool-call
state machine into a sibling streamer, `stream_inference_via_worker`
takes an `Option<(Vec<ImageInput>, u32)>`: when `Some`, prefill is a
single-shot `forward_logits_with_images` splice; when `None`, the
original chunked text-only prefill. Image embeddings are prefill-only,
so every decode step stays on the plain `forward_logits` path and the
shared decode loop is untouched. This keeps exactly one copy of the
tool-call/reasoning logic to maintain.
The Responses API streaming path (`responses_stream`) inherits vision
for free since it drives the same `inference_stream`.
Unit test covers `request_has_images` (the shared routing gate); the
real-weights SSE smoke is the manual curl on beast (cuda-integration).
Closes part of #16 (Stage C1).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
rob thijssen
766c20ba47
