chore: add deno.lock to .gitignore

Deno lock files are auto-generated by the Deno runtime and not needed
for library distribution. Consumers will have their own lock files.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: konard

.gitignore

@@ -140,3 +140,6 @@ vite.config.ts.timestamp-*
 
 # jscpd reports
 reports/
+
+# Deno lock file (generated by Deno runtime - not needed for library distribution)
+deno.lock