feat: improve agent creation workflow and documentation

## BMB Agent Workflow Improvements
- Always create folders for agents (even simple ones)
- Add compact info-and-installation-guide.md (20 lines max)
- Include installation guide with every created agent
- Update workflow to use standalone_output_folder structure

## Documentation Updates
- Clarify --defaults makes installation non-interactive
- Update all parameter documentation for clarity
- Fix npm package references (bmad-method only)

## New Agent Structure
Every agent now gets:
  agent-folder/
  ├── agent-name.agent.yaml    # Source YAML
  └── info-and-installation-guide.md  # Quick install guide + description

## Quick Install Commands (added to guide)
- Interactive: npx bmad-method agent-install --source ./agent.yaml
- Non-interactive: npx bmad-method agent-install --source ./agent.yaml --defaults

This makes agent installation much more user-friendly and consistent.

src/modules/bmb/workflows/create-agent/info-and-installation-guide.md

@@ -0,0 +1,17 @@
+# {agent_name} Agent
+
+## Installation
+
+```bash
+# Quick install (interactive)
+npx bmad-method agent-install --source ./{agent_filename}.agent.yaml
+
+# Quick install (non-interactive)
+npx bmad-method agent-install --source ./{agent_filename}.agent.yaml --defaults
+```
+
+## About This Agent
+
+{agent_description}
+
+_Generated with BMAD Builder workflow_