[CK_TILE] Top-K with Sigmoid kernel

[samremes]

Proposed changes

Add top-k with sigmoid to the existing softmax version. Enabling it also through aiter once this PR is merged: ROCm/aiter#1251

Checklist

Please put an x into the boxes that apply. You can also fill these out after creating the PR. If you're not sure, please don't hesitate to ask.

• I have added tests relevant to the introduced functionality, and the unit tests are passing locally
• I have added the test to REGRESSION_TESTS list defined at the top of CMakeLists.txt in tests/CMakeLists.txt, IF the test takes more than 30 seconds to run.
• I have added inline documentation which enables the maintainers with understanding the motivation
• I have removed the stale documentation which is no longer relevant after this pull request
• (If this change is user-facing) I have added release notes which provide the end users with a brief summary of the improvement from this pull request
• I have run clang-format on all changed files
• Any dependent changes have been merged

Discussion

If this is a relatively large or complex change, feel free to start a discussion by explaining why you chose the solution you did and what alternatives you considered

[Copilot]

Pull Request Overview

This PR extends the existing top-k softmax kernel to support sigmoid activation as an alternative to softmax. The implementation adds a template parameter to control the activation function and updates the API to accept an activation type parameter.

Key changes:

• Added sigmoid activation support alongside existing softmax functionality
• Modified the problem and pipeline templates to accept an ActivationIsSoftmax boolean parameter
• Updated test and example code to support the new activation parameter

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
include/ck_tile/ops/topk_softmax/pipeline/topk_softmax_warp_per_row_problem.hpp	Added ActivationIsSoftmax template parameter to control activation function
include/ck_tile/ops/topk_softmax/pipeline/topk_softmax_warp_per_row_pipeline.hpp	Implemented conditional logic to apply sigmoid or softmax based on the template parameter
include/ck_tile/ops/topk_softmax/kernel/topk_softmax_kernel.hpp	Fixed typo in comment ("tpok" → "topk")
test/ck_tile/topk_softmax/test_topk_softmax_api.hpp	Added activation field to trait struct
test/ck_tile/topk_softmax/test_topk_softmax_api.cpp	Extended dispatch logic to handle sigmoid activation for fp16 and bf16 types
test/ck_tile/topk_softmax/test_topk_softmax.hpp	Added reference implementation for sigmoid, activation parameter, and new test cases
example/ck_tile/09_topk_softmax/topk_softmax_api.hpp	Added activation field to trait struct
example/ck_tile/09_topk_softmax/topk_softmax_api.cpp	Extended dispatch logic to handle sigmoid activation for fp16 and bf16 types
example/ck_tile/09_topk_softmax/topk_softmax.cpp	Added reference implementation for sigmoid and activation parameter support
CHANGELOG.md	Added release note for the new top-k sigmoid kernel

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