Add SeaCache support for Cosmos3 pipelines (#14663)

* Add optional FP32 sampling state for Cosmos3

* Add cache execution contexts to Cosmos3 pipelines

* Add SeaCache support for Cosmos3

* Cap consecutive SeaCache reuses

* Align SeaCache defaults with Cosmos3 inference

* Enable SeaCache by default for Cosmos3

* Document SeaCache for Cosmos3

* Use FP32 sampling state by default for Cosmos3

* Fix SeaCache reconfiguration, transfer state isolation, and FP32 sampling

* Remove SeaCache stats and ablation instrumentation

* Move SeaCache to transformer-level and disable by default

* Align SeaCache and tests with model-level cache patterns

* Make Cosmos3 sampling state always FP32

* Add pipe definition to the docs snippet

* Remove redundant hook registry cache resets

* Use raw vision latents for SeaCache indicators

* Make Cosmos3 SeaCache safe for regional compilation

* Fix SeaCache with Cosmos3 model parallelism

* Support single-stream models in SeaCache

* Add Wan T2V support to SeaCache

* pass denoising step info to cache hooks via cache_context

Replaces SeaCache's pipeline-state callbacks: the pipeline attaches the loop
coordinates (step_index, sigma, num_inference_steps) to the denoiser call with
`cache_context(name, ...)`, carried by a frozen CacheContext dataclass and stored
on each stateful hook's StateManager (the registry no longer holds context).

Co-Authored-By: Dhruv Nair <dhruv.nair@gmail.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Fix Wan cache metadata and Cosmos modular cleanup

Pass denoising step metadata to Wan T2V conditional and unconditional cache contexts.

Restore stateful cache reset after Cosmos modular pipeline calls, restore the required Literal import, and update regression tests and documentation.

* Refactor Cosmos3 SeaCache decoder hook

* Apply CI formatting updates

* Fix distilled system prompt fallback

* Preserve Cosmos3 fp32 sampling state

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Co-authored-by: yiyixuxu <yixu310@gmail.com>
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>