Add claude config and rework bash dotfile management

- Add claude stow package (settings.json, statusline-command.sh)
- Replace .bashrc stow with source-injection approach to avoid conflicts
  with tools like oh-my-bash that want to own ~/.bashrc
- Move all bash customizations into .bashrc.omb, sourced conditionally
- setup.sh now checks for existing source lines before appending

setup.sh

@@ -34,6 +34,13 @@ ensure_sourced() {
 # ssh — always available
 stow_pkg ssh
 
+# claude
+if [ -d "$HOME/.claude" ]; then
+    stow_pkg claude
+else
+    echo "SKIP: claude (~/.claude not found)"
+fi
+
 # bash — stow dotfiles, then ensure ~/.bashrc sources them
 stow_pkg bash
 ensure_sourced "$HOME/.bashrc.omb"