ci: prerelease release builds use local ccache only (no remote reads) (#7249)

[marbre]

Cherry-picks commit 9273e0c into the ROCm 10.0 release branch.

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Motivation

Stable releases are a repackage of the prerelease release-candidate build, so the prerelease compile is what actually ships. Those objects should never come from a remote cache hit to eliminate cache poisoning risks.

• Background: ccache: release-build accuracy risk from compiler_check fingerprint coverage gaps #7248
• Design discussion: Design: ccache accuracy for release builds (fingerprint coverage vs remote cache) #7259

Technical Details

Prerelease builds use the local cache only (remote disabled): zero remote hits, but the local cache still works normally (reads + writes).

• build_tools/setup_ccache.py: now maps nightly-bkc and prerelease values of --release-type to --config-preset=local

Why local-only (not recache or full-disable)

• Keep the local cache: local hits are fine, and some builds (notably Windows) need at least a local cache for performance and runner stability - without one we have seen runners exhaust resources and fail.
• recache was rejected: it forces local misses too, defeating the local cache Windows needs.
• Full-disable was rejected: it removes the local cache and changes build-config parity with nightly/CI.

Test Plan

• build_tools/tests/setup_ccache_test.py (new): pins which release types read the shared remote cache and which are local-only, plus both failure modes above.
• Local: run the tool as each workflow does for ci / dev / nightly / prerelease and compare the emitted config.
• Owner dispatch: a prerelease run shows zero remote hits (local hits fine) in each stage's "Report" step and still builds artifacts; a dev / nightly run is unchanged.

Test Result

CI on this branch, all 9 new tests passing on both platforms:

Check	Result
[Unit Tests ::
ubuntu-24.04](https://github.com/ROCm/TheRock/actions/runs/32395965820/job/96512731944)	pass - 9/9 setup_ccache_test.py
[Unit Tests ::
windows-2022](https://github.com/ROCm/TheRock/actions/runs/32395965820/job/96512731634)	pass - 9/9 setup_ccache_test.py

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pre-commit | pass (black, mdformat, actionlint) |

Windows coverage matters here, not just for parity: IS_WINDOWS selects a different compiler_check mode, and Windows is the platform whose local-cache requirement is the reason this is local-only rather than a full disable.

Cache mode output from running the tool exactly as each workflow invokes it - only prerelease loses the remote, and it keeps its local cache:

[setup_ccache] Cache mode: release_type=ci         preset=github-oss-dev     remote=http://bazelremote-svc.bazelremote-ns...:8080|layout=bazel|connect-timeout=50      local=/tmp/ccache/ci/cache
[setup_ccache] Cache mode: release_type=dev        preset=github-oss-dev     remote=http://bazelremote-svc.bazelremote-ns...:8080|layout=bazel|connect-timeout=50      local=/tmp/ccache/dev/cache
[setup_ccache] Cache mode: release_type=nightly    preset=github-oss-release remote=http://bazelremote-svc-rel.bazelremote-ns...:8080|layout=bazel|connect-timeout=50  local=/tmp/ccache/nightly/cache
[setup_ccache] Cache mode: release_type=prerelease preset=github-oss-release remote=disabled (--no-remote-cache)                                                       local=/tmp/ccache/prerelease/cache

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/TheRock/blob/main/CONTRIBUTING.md.

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