[CK_TILE] Separate PermuteN epilogue from CShuffle epilogue into standalone file (#5863)

## Motivation

The PermuteN epilogue was previously embedded within
cshuffle_epilogue.hpp, despite having fundamentally different behaviour.
Coupling these two independent strategies in one file introduced
unnecessary complexity, SFINAE guards, and a dual operator() overload
selected at compile time via TiledMMAPermuteN_ template parameter.

This PR separates PermuteN into its own standalone
file(pertmuten_epilogue.hpp), simplifying both implementations and
making the codebase easier to maintain and extend independently.

## Technical Details

**New file: permuten_epilogue.hpp:** 
contains PermuteNEpilogueProblem and PermuteNEpilogue, extracted from
the permuteN code path in cshuffle_epilogue.hpp.

**Cleanup of cshuffle_epilogue.hpp:**

- Removed the TiledMMAPermuteN_ template parameter from
[CShuffleEpilogueProblem]
- Removed the SFINAE-guarded permuteN operator() overload
- Removed the EnablePermuateN_ SFINAE alias
- CShuffle now only contains CShuffle logic; EightWave support
(independent feature) is retained

**Consumer migration :**
All consumer files now use compile-time epilogue selection via
[std::conditional_t]

`using GemmEpilogue = std::conditional_t<
    TiledMMAPermuteN,
    PermuteNEpilogue<PermuteNEpilogueProblem<...>>,
    CShuffleEpilogue<CShuffleEpilogueProblem<...>>>;`

**Files modified:**

- flatmm_basic.cpp, moe_flatmm.cpp, a16w4_moe_flatmm.cpp,
mixed_prec_flatmm.cpp, mx_flatmm_instance.hpp — flatmm examples
- run_gemm_quant_example.inc — block-scale GEMM example
- gemm_weight_preshuffle_invoker.hpp — weight preshuffle invoker
- test_gemm_quant_fixtures.hpp, test_gemm_persistent_async_input.cpp,
test_gemm_pipeline_util.hpp — test utilities
- universal_gemm_invoker.hpp — universal GEMM invoker
- epilogue.hpp — add header updated to include permuten_epilogue.hpp



## Submission Checklist

- [x] Look over the contributing guidelines at
https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Adam Osewski <19374865+aosewski@users.noreply.github.com>

example/ck_tile/18_flatmm/flatmm_basic.cpp

@@ -188,27 +188,45 @@ float flatmm_calc(const ck_tile::ScaleFlatmmHostArgs<ScaleM, ScaleN>& args,
         using CodegenFlatmmPipeline =
             ck_tile::FlatmmPipelineAGmemBGmemCRegV1<CodegenPipelineProblem>;
 
-        using GemmEpilogue = ck_tile::CShuffleEpilogue<
-            ck_tile::CShuffleEpilogueProblem<ADataType,
-                                             BDataType,
-                                             DsDatatype,
-                                             AccDataType,
-                                             CDataType,
-                                             DsLayout,
-                                             ELayout,
-                                             CDEElementWise,
-                                             TilePartitioner::MPerBlock,
-                                             TilePartitioner::NPerBlock,
-                                             FlatmmConfig::M_Warp,
-                                             FlatmmConfig::N_Warp,
-                                             FlatmmConfig::M_Warp_Tile,
-                                             FlatmmConfig::N_Warp_Tile,
-                                             FlatmmConfig::K_Warp_Tile,
-                                             CodegenPipelineProblem::TransposeC,
-                                             FlatmmConfig::NumWaveGroups,
-                                             false,
-                                             1,
-                                             FlatmmConfig::TiledMMAPermuteN>>;
+        using GemmEpilogue = std::conditional_t<
+            FlatmmConfig::TiledMMAPermuteN,
+            ck_tile::PermuteNEpilogue<
+                ck_tile::PermuteNEpilogueProblem<ADataType,
+                                                 BDataType,
+                                                 DsDatatype,
+                                                 AccDataType,
+                                                 CDataType,
+                                                 DsLayout,
+                                                 ELayout,
+                                                 CDEElementWise,
+                                                 TilePartitioner::MPerBlock,
+                                                 TilePartitioner::NPerBlock,
+                                                 FlatmmConfig::M_Warp,
+                                                 FlatmmConfig::N_Warp,
+                                                 FlatmmConfig::M_Warp_Tile,
+                                                 FlatmmConfig::N_Warp_Tile,
+                                                 FlatmmConfig::K_Warp_Tile,
+                                                 CodegenPipelineProblem::TransposeC,
+                                                 false,
+                                                 1>>,
+            ck_tile::CShuffleEpilogue<
+                ck_tile::CShuffleEpilogueProblem<ADataType,
+                                                 BDataType,
+                                                 DsDatatype,
+                                                 AccDataType,
+                                                 CDataType,
+                                                 DsLayout,
+                                                 ELayout,
+                                                 CDEElementWise,
+                                                 TilePartitioner::MPerBlock,
+                                                 TilePartitioner::NPerBlock,
+                                                 FlatmmConfig::M_Warp,
+                                                 FlatmmConfig::N_Warp,
+                                                 FlatmmConfig::M_Warp_Tile,
+                                                 FlatmmConfig::N_Warp_Tile,
+                                                 FlatmmConfig::K_Warp_Tile,
+                                                 CodegenPipelineProblem::TransposeC,
+                                                 FlatmmConfig::NumWaveGroups>>>;
 
         // ToDo: Will add the codegen part to test different pipeline policies in GEMM.
         // Now we only use the BlockGemmASmemBSmemCRegV1DefaultPolicy.
@@ -230,6 +248,7 @@ float flatmm_calc(const ck_tile::ScaleFlatmmHostArgs<ScaleM, ScaleN>& args,
                       << "Shape: " << CodegenFlatmmShape::GetName() << "\n"
                       << "problem: " << CodegenPipelineProblem::GetName() << "\n"
                       << "pipeline: " << CodegenFlatmmPipeline::GetName() << "\n"
+                      << "epilogue: " << GemmEpilogue::GetName() << "\n"
                       << "grid: {" << grids.x << ", " << grids.y << ", " << grids.z << "}"
                       << ", blocks: {" << blocks.x << ", " << blocks.y << ", " << blocks.z << "}"
                       << std::endl;