docs: require Khronos validation layer for AGC and shader testing

AGENTS.md

@@ -12,3 +12,4 @@ AnyPS5 relinks PS5 executables into native Linux or Windows programs that run ag
 - Before pushing run `python3 tools/check_conventions.py --base origin/main`; before opening run `python3 tools/pr_overlap.py --branch <branch>`.
 - Build and test: [BUILD](docs/dev/BUILD.md); a relinker-only change builds with `-DANYPS5_RELINKER_ONLY=ON`.
 - A speed claim shows `tools/trace_digest.py` summaries of `main` and of the change from the same machine and scene.
+- AGC, shader recompiler and VideoOut changes: run the same focused tests on `main` and the change with `ANYPS5_REQUIRE_VULKAN=1`, `ANYPS5_NO_SHADER_CACHE=1` and `VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation` using `ctest --test-dir build -R <pattern> -V` from the same machine and GPU. Confirm neither log contains `was not found but was requested by env var VK_INSTANCE_LAYERS`, then compare the logs and confirm the change adds no new `VUID-` validation errors (`ctest` can report `Passed` when validation errors are logged).

CONTRIBUTING.md

@@ -64,7 +64,7 @@ The [pull request template](.github/pull_request_template.md) is the checklist f
 - The PR overlap comment lists open pull requests that change the same lines or exports; agree with their authors which one goes first and declare it with `Depends on`.
 - Run the tests before opening the pull request and describe what was tested (OS, title or homebrew).
 - A pull request that claims a change in speed shows the summary lines of `main` and of the change, from the same machine and scene, and attaches the traces, captured as the [Performance report](.github/ISSUE_TEMPLATE/performance.yml) issue form describes. A slow scene is reported with the same form. A pull request titled `perf(...)` or `perf:` is labeled `perf`, and `perf numbers missing` until its description holds two valid summary lines with different commits.
-- Changes to the AGC driver, the shader recompiler or VideoOut name each GPU the GPU tests ran on (vendor, model, driver, OS) on the `GPUs tested` checklist line. CI runs these tests only on lavapipe, and hardware drivers fail where lavapipe and other vendors pass, so a reviewer can ask for a run on another vendor before merging.
+- Changes to the AGC driver, the shader recompiler or VideoOut run the same focused tests on `main` and the change with `VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation`, `ANYPS5_NO_SHADER_CACHE=1` and `ANYPS5_REQUIRE_VULKAN=1` using `ctest -V` from the same machine and GPU, confirm neither log reports `was not found but was requested by env var VK_INSTANCE_LAYERS`, confirm the change introduces no new `VUID-` validation errors compared with `main`, and name each GPU the GPU tests ran on (vendor, model, driver, OS) on the `GPUs tested` checklist line. CI runs these tests only on lavapipe, and hardware drivers fail where lavapipe and other vendors pass, so a reviewer can ask for a run on another vendor before merging.
 - Investigation notes, reports, screenshots and logs go in the pull request, not in the repository. Images for documentation go in the [gist](https://gist.github.com/boykopovar/0e53f2e1426f29ecd41e3b51540b8a90) comments.
 - Say whether the change was written with AI assistance. The author of the pull request is responsible for every line of it.