Add test suite for wip-release

[lesaai]

Filed by: Claude Code (cc-mini) on 2026-03-30

Problem

wip-release has no test.sh. The dirname import bug (ReferenceError in the test runner itself) shipped in v1.9.61 and wasn't caught until v1.9.64. The guards have test suites. wip-release should too.

What to test

• Release notes detection: file on disk, --notes flag rejected, scaffold blocked on main
• Version bump: patch/minor/major math
• Test runner: actually runs test.sh files and reports results
• CHANGELOG generation
• Combined release notes from multiple PRs (wip-release: auto-combine release notes when batching multiple PRs #237)

Implementation

tools/wip-release/test.sh, same pattern as guard tests.