feat(cli): add headless/non-interactive installation mode

[AlexSuprun]

Summary

• Add headless/non-interactive installation mode for CI/CD pipelines and script-based automation
• Introduce HeadlessConfigBuilder class for parsing CLI options and config files
• Support both JSON and YAML configuration file formats

New CLI Flags

Flag	Short	Description	Default
--headless	-H	Non-interactive mode	false
--config <path>		Config file path (JSON/YAML)	none
--directory <path>		Installation directory	cwd
--modules <list>	-m	Comma-separated modules	bmm
--ides <list>	-i	Comma-separated IDEs	claude-code
--skip-ides		Skip IDE configuration	false
--user-name <name>		Agent communication name	system user
--language <lang>		Communication language	English
--doc-language <lang>		Document output language	English
--output-folder <path>		Output folder	_bmad-output
--action <type>		install/update/quick-update	install
--force	-f	Force overwrite existing	false
--yes	-y	Accept defaults (implies headless)	false

Usage Examples

# Quick install with defaults
npx bmad-method install --headless

# Install with specific modules and IDEs
npx bmad-method install --headless -m bmm,bmb -i claude-code,cursor

# Install from config file
npx bmad-method install --config bmad-config.yaml

Test plan

• All 40 headless installation tests pass
• Existing test suite passes (npm test)
• Lint and format checks pass
• Manual testing of headless installation in clean directory
• Manual testing of config file loading (YAML and JSON)