fix(ci): drop missing stale-claim label exemption

[GHX5T-SOL]

Title
fix(ci): drop missing stale-claim label exemption

Summary

• remove the stale-claim sweep exemption for a long-running label that does not exist in this repository
• keep the existing pinned exemption intact

Why
The sweep currently checks both pinned and long-running, but long-running is not one of the repository labels. That makes the second branch dead code and can make the claim-release behavior look like it has an exemption that maintainers cannot apply.

Fixes #27

Validation

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/unassign-stale.yml"); puts "yaml ok"'
• make test
• PATH=/Users/brucewayne/Money/tools/go/bin:$PATH make lint
• git diff --check
• git diff --check HEAD~1 HEAD
• git diff | gitleaks stdin --no-banner --redact
• git show --format= --patch HEAD | gitleaks stdin --no-banner --redact

Notes

• golangci-lint was installed locally under /Users/brucewayne/Money/tools/go/bin because it was not already on PATH.
• I did not run workflow_dispatch because this workflow can warn or unassign live issues; validation was static syntax plus repository tests/lint.

[github-actions]

First PR — welcome aboard!

A few things to expect:

1. CI: every PR runs build + race tests + lint on Ubuntu and macOS. If something fails, the log will tell you exactly which gate.
2. DCO: every commit needs Signed-off-by:. git commit -s adds it automatically.
3. Conventional Commits: PR titles like feat(analyze): new rule or fix(cli): handle X. We squash-merge by default.
4. Review: a maintainer will review within 72 hours. Suggestions are conversations, not orders — push back if something doesn't fit your context.

If you get stuck, reply here or jump to Discussions. We want this PR to land.