Route build outputs to dist/ and commit release artifacts

build.ps1 now always packages the .vsix and writes both artifacts to
dist/. Added .vscodeignore so the .vsix excludes Go source, TS source,
and other dev-only files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -93,7 +93,6 @@ out
 
 # Nuxt.js build / generate output
 .nuxt
-dist
 
 # Gatsby files
 .cache/