fix(xiaoyunque): register reference image assets

[superche]

Summary

• register legacy upload_file image results through the first-party AssetCreateV2 contract when pippit_asset_id is missing or blank
• keep EverPhoto asset_id and PippitAssetID as distinct identities and send only the registered PippitAssetID into generation
• use the same reference upload/registration contract for both image and video generation
• assert every governed image and video model advertises reference-image input support
• fail before submit_run with a stable safe diagnostic when registration is rejected or incomplete
• release xiaoyunque-generation 0.3.4 with companion 0.3.2 and advance Registry sequence to 23

Why

Reference workflows could stop after upload because upload_file may return only an EverPhoto asset id, while both image and video submission require the registered Pippit asset identity. The previous sidecar parsed pippit_asset_id as optional and then failed generically before submission.

Safety

• no fallback aliases asset_id as PippitAssetID
• registration errors do not create an operation record or call submit_run
• public errors contain no upstream body, Cookie, native path, or asset identifier
• direct upload responses that already contain pippit_asset_id remain unchanged

Validation

• rebased onto current origin/main (542be60)
• bun run check passed outside the restricted loopback sandbox
• XiaoYunque sidecar tests: 109 passed, including registered Canvas reference images for image and video generation
• repository tooling tests: 52 passed
• typecheck, local/darwin-arm64 companion builds, Registry validation, package packing, and index generation passed

No live or billable XiaoYunque generation was triggered during validation.