Loading the IP-Adapter (958d2e09) fixed the mechanism, but only AnimateDiff-class
pipelines have one. On Wan / CogVideoX / LTX / SVD — the models people actually
use — character_profiles still did nothing except prepend the profile name to the
prompt, so identity was not working where it mattered.

The image endpoint does have real IP-Adapter. So when a video model can't
condition on references itself, render the first frame there against the same
profiles and run the video as ti2v from that keyframe. This is the recipe
tools/videogen.py already drives by hand, now done server-side.

It runs BEFORE the video pipeline is loaded, so an image model and a video model
are never resident at once, and it dispatches through the front (execute_api_request)
so the image model may live on a different engine.

New request fields: keyframe_identity (auto | always | never), keyframe_model,
keyframe_steps. 'auto' skips the bridge when the model has native IP-Adapter or a
first frame was already supplied.

If the keyframe can't be rendered the request still proceeds — identity degrades
to the prompt hint plus any per-character LoRA and the reason is reported in the
response warnings — unless the caller asked for 'always', which is an explicit
requirement and so returns 502 rather than silently producing a stranger.

Verified offline across every branch: bridge fires for Wan and rewrites to ti2v
with the keyframe; skipped for AnimateDiff; forced by 'always'; disabled by
'never'; no-op with no profiles or an existing first frame; degrades with a
warning on image-endpoint failure and raises 502 under 'always'.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R6iugoNeEgt9PkajKrFyq4