A test pins finishing a conflict from the forge: a stale head, a pull with no conflict, or the wrong path is refused #7088

finishConflicts in src/actions/finish-conflicts.ts refuses with stale, no_conflicts and not_resolvable, and no test names any of them.

Done:

• [ ] A new test makes a pull that conflicts on one file and finishes it with that path's resolution. The pull is then mergeable.
• [ ] A head or base that moved since the page was read is stale. A pull with no conflict is no_conflicts. A path that is not the one conflicting file, or a pull that conflicts on two files, is not_resolvable.
• [ ] After each refusal, the head branch is unchanged.

Files: test/finish-conflicts-refusals.test.ts

If the test finds the behaviour wrong, fix the action in the same pull and say so. If the check fails in a test this pull does not touch, name it in the pull rather than widening the change.

Before pushing: bun x tsc --noEmit and the new test.