[SVLS-4902] Add DDCI release orchestration

[Lewis-E]

What does this PR do?

Adds the repository-owned portion of the SVLS-4902 control plane:

• GitLab Rust checks for merge requests and main across Linux amd64, Linux arm64, and Windows 2022
• the static Full DDCI release rule and authenticated ddr launcher
• repository-scoped tag, branch, GitHub Actions dispatch, run-correlation, polling, token-refresh, and result-recording helpers
• the draft, publish, and release orchestration graph for core plus the five language packages
• actor-gated, retry-safe core binary and npm release workflows
• automatic dispatch of the dd-trace-dotnet dependency updater after successful NuGet publication

Motivation

SVLS-4902 makes Full DDCI the single operator entry point while retaining GitHub-hosted npm/PyPI trusted publishing and core npm provenance.

Additional Notes

The missing serverless-components GitLab project blocks authoritative OIDC claims, inbound dd-octo-sts policies, managed-App actor configuration, CodeSync/DDCI setup, runner assignment, ruleset bypass, and live central dispatch. No identity values or policies are guessed in this PR.

Describe how to test/QA your changes

No new validation was added or run beyond existing CI, per the approved delivery boundary. The repository's pre-push hook ran cargo fmt --check and cargo clippy successfully while pushing this branch. This draft should remain blocked from release execution until the GitLab project and external identity/settings prerequisites exist.