Add pre-commit hooks for code quality (#19)

## Summary
- Add pre-commit framework with hooks for YAML, Ansible, Python, shell, TOML, JSON, and secret detection
- Fix all 91+ ansible-lint violations (variable naming, handler capitalization, changed_when)
- Fix shellcheck warnings in mise-tasks scripts
- Document pre-commit setup in README.md

## Deployment and Testing
- [x] All pre-commit hooks pass (`uvx pre-commit run --all-files`)
- [x] Test ansible playbook with `--check` mode
- [x] Run `mise run indri-services-check` after deploy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: https://forge.tail8d86e.ts.net/eblume/blumeops/pulls/19

ansible/roles/node_exporter/tasks/main.yml

@@ -13,10 +13,10 @@
     src: node_exporter.args.j2
     dest: /opt/homebrew/etc/node_exporter.args
     mode: '0644'
-  notify: restart node_exporter
+  notify: Restart node_exporter
 
 - name: Ensure node_exporter service is started
   ansible.builtin.command: brew services start node_exporter
-  register: brew_start
-  changed_when: "'Successfully started' in brew_start.stdout"
+  register: node_exporter_brew_start
+  changed_when: "'Successfully started' in node_exporter_brew_start.stdout"
   failed_when: false