feat(autotuner): enable per-op autotune bypass for faster framework warmup (#3396)

Add skip_ops to let frameworks exclude specific ops from autotuning,
falling back to heuristic tactics without kernel compilation overhead.
addresses #3295: mm_fp4 cute-dsl autotuning is slow due to compilation.

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## Summary by CodeRabbit

* **New Features**
* Added an option to exclude specific custom operations from profiling
via the tuning context, with nested contexts combining exclusions and
restoring prior state on exit.
* Excluded operations immediately use fallback behavior and bypass
profiling and cache writes.

* **Tests**
* Added tests validating skip behavior, nesting/restore semantics,
fallback selection, and that skipped ops don’t affect profiling cache.

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Co-authored-by: Albert Cheng (Engrg-Hardware 1) <albecheng@login-lyris01.lyris.clusters.nvidia.com>