Add pre-commit hooks for code quality and fix all lint violations

Introduces pre-commit framework with hooks for:
- General file hygiene (trailing whitespace, EOF, large files)
- Secret detection (TruffleHog)
- YAML linting (yamllint)
- Ansible linting (ansible-lint)
- Python linting/formatting (ruff)
- Shell script analysis (shellcheck, shfmt)
- TOML formatting (taplo)
- JSON formatting (prettier)

Fixes 91+ ansible-lint violations:
- Renamed variables to use role prefixes (e.g., brew_start -> alloy_brew_start)
- Capitalized handler names per convention
- Added changed_when to command tasks
- Fixed template usage in task names

Fixes shellcheck warnings:
- Removed unused variables
- Fixed SC2155 (declare and assign separately)

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

ansible/roles/forgejo/tasks/main.yml

@@ -18,11 +18,12 @@
       Forgejo config not found at /opt/homebrew/var/forgejo/custom/conf/app.ini
       This file contains secrets and is not managed by ansible.
       To restore from backup, run:
-        borgmatic --config ~/.config/borgmatic/config.yaml extract --archive latest --path /opt/homebrew/var/forgejo/custom/conf/app.ini
+        borgmatic --config ~/.config/borgmatic/config.yaml extract --archive latest \
+        --path /opt/homebrew/var/forgejo/custom/conf/app.ini
   when: not forgejo_config.stat.exists
 
 - name: Ensure forgejo service is started
   ansible.builtin.command: brew services start forgejo
-  register: brew_start
-  changed_when: "'Successfully started' in brew_start.stdout"
+  register: forgejo_brew_start
+  changed_when: "'Successfully started' in forgejo_brew_start.stdout"
   failed_when: false