chore: gitignore local canvas snapshot directories (#127)

The *-local pattern predates the canvas visual regression run and
missed the new chromium-local-canvas directory. Generalize to *-local*
so all local-environment snapshot dirs stay untracked; chromium-ci*
baselines remain committed.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: chiefcll

.gitignore

@@ -6,7 +6,7 @@ dist
 dist-*
 examples/dist-tsc
 visual-regression/failed-results
-visual-regression/certified-snapshots/*-local
+visual-regression/certified-snapshots/*-local*
 build
 releases
 .tmp