fix(release): dispatch release-please on release/candidate branch

[Jacksunwei]

Summary

• Add --ref release/candidate to gh workflow run in release-cut and release-cherry-pick
• Without this, workflow_dispatch defaults to main, so release-please runs on the wrong branch and skips (since the branch check added in fix(release): skip release-please when release/candidate is renamed #83 correctly detects it's not on release/candidate)

Root cause: pushes with GITHUB_TOKEN don't trigger other workflows (GitHub's design), so the push trigger in release-please.yml never fires — the explicit gh workflow run dispatch is the only trigger, and it was missing --ref.

Test plan

• Run release-cut and verify release-please creates a changelog PR on release/candidate

[gemini-code-assist]

Note

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