feat(ascend): add validated RWKV-7 V1 plugin

[123123213weqw]

What changed

Adds plugins/rwkv7-vllm-ascend, a separately installable vLLM V1 model plugin for RWKV-7 on Huawei Ascend. It provides:

• vLLM V1 MambaSpec recurrent state for fp32 WKV plus attention/FFN token shifts
• continuous/dynamic batching, irregular chunked prefill, mixed decode+prefill, cancellation, slot reuse, and stale-state zeroization
• standard Hugging Face safetensors loading, native embeddings/LM head/logits processing, and OpenAI serving compatibility through vLLM
• exact-stack fail-closed admission for Ascend 910B3, vLLM/vllm-ascend 0.18.0, CANN 8.5.0, and torch/torch_npu 2.9.0
• default-off W8/W4 packed FFN integration seams that reject production claims
• reproducible compatibility setup, unit/contract tests, one-command real-engine acceptance, and hashed evidence

The implementation remains out of vLLM core so the Huawei runtime and its incompatible vendor package pins can be installed independently.

Duplicate-work check

Upstream vLLM PR #48686 adds minimal native RWKV7 model support. This PR is materially different: it targets the vllm-ascend vendor runtime, implements physical recurrent cache-slot lifecycle and scheduler trace gates, and is packaged as an out-of-tree hardware plugin. Searches for open RWKV Ascend PRs in both upstream vLLM and this fork returned no duplicate.

Ascend 910B3 validation

Exact proposed plugin tree, real fla-hub/rwkv7-7.2B-g0a checkpoint:

• 13.4100 GB dense model weights loaded through vLLM V1
• input lengths 1, 47, and 180; repeated in reverse order
• max_num_batched_tokens=32: 455 actual prefill tokens over 16 prefill steps
• 6 mixed decode+prefill steps and 3 multi-prefill-request steps
• 5 fresh and 14 continuation recurrent segments
• physical Mamba slots [2, 3] reused, observed nonzero before clear, and zero after clear
• exact greedy Hello IDs [45, 308, 459]
• repeated outputs identical; final status ACCEPTANCE_OK
• the scheduler trace SHA256 2f5a8c...c2d6 reproduced across three independent runs

Quantization status

The packed formats reduce isolated FFN weight payload to about 50.024% (W8) and 26.5625% (group-128 W4) of FP16. Production admission remains disabled: the clean dispatch profile found W4 module-path regression on the expansion projection (minimum 0.913x FP16), and neither format has a whole-model E2E gate. Manifests claiming production_accepted=true are rejected.

Checks

• uvx ruff check plugins/rwkv7-vllm-ascend/{rwkv7_vllm_ascend,tests_vllm}: passed
• uvx ruff format --check ...: passed
• uv build plugins/rwkv7-vllm-ascend: sdist and wheel built
• real vLLM/vllm-ascend environment: 18 passed
• exact PR plugin real 7.2B engine acceptance: ACCEPTANCE_OK
• committed evidence SHA256 manifests: passed

AI assistance was used. This is a draft for the human submitter to review line by line and defend before promotion or upstream submission.

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[123123213weqw]

Withdrawn in favor of the self-contained Huawei Ascend monorepo delivery. The final formatted vLLM V1 plugin and real-engine evidence are now canonical under vllm-rwkv-ascend/ in rwkv-rs/rwkv7-ascend-npu#3 (consolidation commit 12bbcd9).