chore: add uv.lock to .gitignore

uv.lock was untracked and showing in git status. Since this is a
library (not an application), lock files should not be committed —
consumers resolve their own dependency versions.

Closes #146

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antoineleclair

.gitignore

@@ -25,6 +25,9 @@ wheels/
 venv/
 ENV/
 
+# uv lock file (library — consumers resolve their own deps)
+uv.lock
+
 # IDE
 .idea/
 .vscode/