Announce releases in repo and org Discussions #182

Goal

Post each release to GitHub Discussions in two places, matching codeanalyzer-typescript/-python/-java:

• Repo-level — the softprops/action-gh-release publish step opens a Discussion linked to the release (category Announcements), seeded from the generated changelog. Needs discussions: write in the workflow permissions: block, and the action bumped v1 → v2 (v1 is on deprecated Node16 and predates reliable discussion_category_name support).
• Org-level — a new step posts the same changelog into codellm-devkit/.github → Announcements via a createDiscussion GraphQL mutation, authenticated by the org-level ORG_DISCUSSIONS_TOKEN secret. continue-on-error so a failed org post never sinks an otherwise-good release.

Prerequisites (done)

• Discussions already enabled on this repo; Announcements category exists.
• ORG_DISCUSSIONS_TOKEN org secret has repo scope.

Done when

Both discussion posts appear on the next release. Patch bump (1.2.0 → 1.2.1) included so a release can exercise it.