feat(model-manager): support LyCORIS LoKr LoRAs for Krea-2 - #9424

Summary

Krea-2 LoRAs in LyCORIS LoKr format can't be installed at all at the moment. The probe turns them away with:

model does not match Krea-2 LoRA heuristics (no complete lora_A/B or lora_down/up pair)

I hit this with an adapter trained in ai-toolkit, which emits LoKr by default, so I'd guess a fair few of the Krea-2 LoRAs going around are in the same boat.

The Krea-2 probe only knows about lora_A/lora_B and lora_down/lora_up. LoKr carries Kronecker factors instead (lokr_w1/lokr_w2, or the factored _a/_b pairs plus an optional lokr_t2), so _has_complete_lora_pair() says no and the adapter is never identified. Setting the base by hand doesn't get you anywhere either, that path goes through the same helper.

There's a second one further down: _SUFFIX_TO_VALUE_KEY doesn't list the lokr_* suffixes, so even past the probe _group_by_layer() would drop the weights and leave every layer holding nothing but its alpha.

The rest was already there. LoKRLayer exists, any_lora_layer_from_state_dict() reaches for it the moment it sees lokr_w1, and the Qwen-Image converter handles LoKr fine. Only the Krea-2 side was never wired up, which fits it being marked WIP in #9304.

So this adds the two missing pieces: a _has_lokr_layer() helper that both config gates consult, and the lokr_* suffixes in the converter's suffix map. I left the signature-module check alone, so a LoKr that only touches generic transformer blocks still won't be claimed as Krea-2.

Related Issues / Discussions

Follows on from #9304.

QA Instructions

Take any ai-toolkit LoKr for Krea-2 (keys look like diffusion_model.txtfusion.<block>.attn.wq.lokr_w1) and install it through the Model Manager. Before, it's rejected with the error above. After, it installs as base=krea-2, format=lycoris and turns up in the LoRA picker.

I tested with a 32-module adapter on the text-fusion stage against a GGUF-quantised Krea-2 Turbo. It converts to 32 LoKRLayers, every target key resolves to a real nn.Linear in Krea2Transformer2DModel, the reconstructed weight (4×4 ⊗ 640×640 = 2560×2560) matches the layer it patches, and generation comes out visibly different with the LoRA switched on.

8 new tests, covering full and factored LoKr, the native→diffusers key renaming, and that a LoKr without the Krea-2 signature modules still gets turned away. tests/backend/patches/ and tests/backend/model_manager/ pass (1030 passed, 133 skipped, 1 xfailed), as do ruff check and format. I only ran them on 3.12/Windows locally, so the rest of the matrix is on CI.

Merge Plan

Nothing special, backend only.

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Tests added / updated (if applicable)
• ❗Changes to a redux slice have a corresponding migration
• Documentation added / updated (if applicable)
• Updated What's New copy (if doing a release after this PR)