chore: gitignore devlog/, remove from tracking

Devlogs are workspace-local, not repo artifacts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: lroolle

.gitignore

@@ -4,3 +4,4 @@ dist/
 .env
 .env.*
 .npmrc
+devlog/