[ET-VK] buffer implementation of rotary positional embeddings

[SS-JIA]

Stack from ghstack (oldest at bottom):

• -> [ET-VK] buffer implementation of rotary positional embeddings #15620
• [ET-VK] Implementation of to_dim_order_copy #15619
• [ET-VK][ez] Fuse update_cache + custom_sdpa into sdpa_with_kv_cache #15618
• [ET-VK] Implement select_at_dim_as_symint #15617
• [ET-VK][ez] Add lint rule to check no debug mode in shaders + clean up debug mode usage #15616

Title says it all!

Differential Revision: D86340338

[pytorch-bot]

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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/15620

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✅ You can merge normally! (7 Unrelated Failures)

As of commit 1832253 with merge base 2b02316 ():

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• Test CUDA Builds / test-model-cuda-e2e (google, gemma-3-4b-it, quantized-int4-tile-packed) / linux-job (gh) (detected as infra flaky with no log or failing log classifier)

BROKEN TRUNK - The following jobs failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / test-binary-size-linux-gcc / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / test-openvino-linux / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / test-setup-linux-gcc / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest / windows / windows-job (gh) (trunk failure)
  backends/xnnpack/test/ops/test_conv1d.py::TestConv1d::test_qs8_conv1d_batchnorm_seq
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  backends/xnnpack/test/ops/test_conv1d.py::TestConv1d::test_qs8_conv1d_batchnorm_seq
• Test Metal Backend / export-voxtral-metal-artifact / macos-job (gh) (trunk failure)
  /Users/ec2-user/runner/_work/executorch/executorch/pytorch/executorch/pip-out/temp.macosx-11.0-arm64-cpython-311/cmake-out/configurations/optimized_native_cpu_ops_lib/NativeFunctions.h:72:228: error: no template named 'optional' in namespace 'torch::executor'; did you mean 'executorch::aten::optional'?

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