Lint now catches "wip" and "fix stuff" filler bullets

The changelog linter has a new check: Bullets say what changed. Entries whose bullets are zero-information filler — wip, fix stuff, merged PR #142, minor fixes, bare cleanup — now get flagged (and fail the check when most bullets are filler).

We found the gap ourselves: a changelog whose latest entry was literally three filler bullets graded A/92. It now grades B/75 with a FAIL and a per-entry note telling you which bullet says nothing.

Informative bullets are safe: the check matches only whole-bullet filler after stripping PR refs and links, so "Fixed the dropdown crash" or "Updated dependencies" never trip it. Verified against major OSS changelogs (Vue, Axios, Prettier, Tailwind) — zero false positives.

Try it: [/lint](/lint) or POST /api/v1/lint — no auth needed.