Bazel C/C++ Toolchains for S-CORE release v1.0 #3222

Summary

Prepare and publish score_bazel_cpp_toolchains for the S-CORE v1.0 release.

This issue tracks the release readiness work for the Bazel C/C++ toolchain configuration repository used by S-CORE. The repository provides Bazel module extension logic, package metadata, templates, and validation examples for Linux and QNX toolchains. It does not ship compiler binaries directly.

Goal

Deliver a release-ready bazel_cpp_toolchains version aligned with the S-CORE v1.0 release, including validated toolchain definitions, updated documentation, and reproducible package metadata.

Scope

The release should cover:
TBD

Proposed Deliverables

• Release tag/version for bazel_cpp_toolchains aligned with S-CORE v1.0
• Reviewed and updated packages/version_matrix.bzl
• Verified generated toolchain repositories for supported platforms
• Successful test workspace smoke-test runs for relevant configurations
• Updated release-facing documentation
• Release notes summarizing supported toolchains, changes, and known limitations

Validation Expectations

Before closing this issue, verify:

• Bazel module extension usage works for supported toolchains
• Default package resolution is correct for release-targeted versions
• Toolchain registration and platform matching succeed
• Example targets compile and link successfully for the supported matrix
• QNX-specific package/licensing flow is documented and validated as far as release policy allows

Acceptance Criteria

• A releasable bazel_cpp_toolchains version is identified and tagged for S-CORE v1.0
• Supported Linux and QNX toolchain configurations are validated in the example workspace
• Package metadata, URLs, checksums, and templates are up to date
• Documentation reflects the final release surface
• Known gaps or unsupported scenarios are explicitly documented

Checklist

• Confirm target release version and tag naming
• Review supported platform/toolchain matrix for v1.0
• Update package metadata as needed
• Validate Linux host and cross toolchain scenarios
• Validate runtime-specific Linux variants
• Validate packaged QNX toolchain scenarios
• Review templates and generated configuration outputs
• Update README/docs for the released surface
• Prepare release notes
• Publish/tag release