[feature] Extract C++ code to jinja template files

[jbelloncastro]

Motivation

This PR aims to improve readability and maintainability by separating the C++ codegen logic from the file contents.

This is merely a feature proposal and therefore the changes are contained within a single source directory (csrc/ck_gemm_a8w8/)

Technical Details

The C++ code is placed in jinja template files. This makes the python code easier to read as it only needs to produce the appropriate data structures, while the code resides in its own files. The changes thus far are contained within csrc/ck_gemm_a8w8/, but are applicable to the rest of csrc/ subdirectories. This potentially enables reuse across modules, since many of the generated files have very similar structure.

Test Plan

1. Generate source files. The result files should be nearly identical to the original and also compile successfully.

GPU_ARCHS='gfx950;gfx942' python gen_instances.py -w /tmp -f ../../aiter/configs/a8w8_tuned_gemm.csv

3. CI regression should not produce any test regressions

Test Result

All files match

Submission Checklist

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

[github-actions]

🏷️ CI Guide

Runs automatically on every PR:

• ✅ Pre-checks (submodule verification, code formatting)
• ✅ Aiter op tests (gfx942 + gfx950)
• ✅ Triton tests on MI35X (only when aiter/ops/triton/** or related paths are changed)

Extended tests (opt-in via labels):

Label	Tests
ci:triton-300x	Run an additional Triton test job on MI300X in PRs; main branch always runs both MI35X and MI300X
ci:sglang	SGLang integration tests: DeepSeek-R1-MXFP4 accuracy, Qwen 3.5 accuracy
ci:atom	ATOM benchmark: DeepSeek-R1-0528, GPT-OSS-120B
ci:atom_full	ATOM accuracy suite for PR and main models from ATOM models_accuracy.json
ci:vllm	vLLM benchmark: GPT-OSS-120B, DeepSeek-R1-0528, Kimi-K2.5
ci:all	All standard extended tests (excludes ci:atom_full)

Only add ci:atom_full for FlyDSL or Triton upgrades.
Add labels via the sidebar or gh pr edit 3801 --add-label <label>

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