v0.4.0

comment-policy/no-decorative-comment: cover Unicode dividers

The decorative-marker charset was ASCII-only, so section banners built from
Unicode box-drawing characters passed lint untouched. The rule now detects them,
in both // and /* */ forms.

Now caught:

• box-drawing rows and frames — /* ────────── */, /* ══════ Section ══════ */, /* ── Title ────── */
• en/em-dash rows — /* ———————— */
• ~ runs — // ~~~~~~~~

Unchanged:

• ASCII behavior (=====, ---, #region, ===text===)
• a single divider glyph inside prose stays clean (e.g. 5–10, push — иначе, timeout │ retry)
• fix semantics — // banners autofix (line removed), /* */ banners are report-only

Full Changelog: v0.3.0...v0.4.0