CI: fix release asset upload token permission

[aniongithub]

Problem

The Release Docker Image workflow failed on v0.63 at the Upload OpenAPI spec to release step with:

Resource not accessible by integration - https://docs.github.com/rest/releases/releases#update-a-release

The image built and pushed fine; only the release-asset upload failed.

Root cause

The dedicated MEMORYALPHA_RAG_API_MODIFY_RELEASE_TOKEN was passed to softprops/action-gh-release@v2 as a GITHUB_TOKEN env var. But that action's token input defaults to github.token, and per its docs "A non-empty explicit token overrides GITHUB_TOKEN." So the default token won — and the workflow only granted it contents: read, which can't modify releases.

Fix

• Pass the PAT as the token input under with: (so it's actually used).
• Bump workflow permissions to contents: write as a fallback so the default token can also write releases.

Unrelated to the earlier port fix (the OpenAPI-generate step passed). After merge, cut a new release to verify the asset uploads.