Switch default merge_method from 'merge' to 'squash' so dev->main PRs collapse the dev branch's incremental commits into one squash commit on main, keeping main's history linear and release-tag-friendly. Affects: workflow_dispatch input default, decide-step initial value + workflow_dispatch fallback, both push-trigger branches (tag + commit-msg), and the case-statement fallback in the auto-merge step. CONTRIBUTING.md updated to reflect the new default.
手瓜一十雪
3afbcfaae5