feat: enhance QA agent as senior developer with code review capabilities and major brownfield improvements

This release introduces significant enhancements across multiple areas:

QA Agent Transformation:
- Transform QA agent into senior developer role with active code refactoring abilities
- Add review-story task enabling QA to review, refactor, and improve code directly
- Integrate QA review step into standard development workflow (SM → Dev → QA)
- QA can fix small issues directly and leave checklist for remaining items
- Updated dev agent to maintain File List for QA review focus

Knowledge Base Improvements:
- Add extensive brownfield development documentation and best practices
- Clarify Web UI vs IDE usage with cost optimization strategies
- Document PRD-first approach for large codebases/monorepos
- Add comprehensive expansion packs explanation
- Update IDE workflow to include QA review step
- Clarify agent usage (bmad-master vs specialized agents)

Brownfield Enhancements:
- Create comprehensive Working in the Brownfield guide
- Add document-project task to analyst agent capabilities
- Implement PRD-first workflow option for focused documentation
- Transform document-project to create practical brownfield architecture docs
- Document technical debt, workarounds, and real-world constraints
- Reference actual files instead of duplicating content
- Add impact analysis when PRD is provided

Documentation Task Improvements:
- Simplify to always create ONE unified architecture document
- Add deep codebase analysis phase with targeted questions
- Focus on documenting reality including technical debt
- Include Quick Reference section with key file paths
- Add practical sections: useful commands, debugging tips, known issues

Workflow Updates:
- Update all 6 workflow files with detailed IDE transition instructions
- Add clear SM → Dev → QA → Dev cycle explanation
- Emphasize Gemini Web for brownfield analysis (1M+ context advantage)
- Support both PRD-first and document-first approaches

This release significantly improves the brownfield development experience and introduces a powerful shift-left QA approach with senior developer mentoring.

bmad-core/agents/analyst.md

@@ -16,7 +16,7 @@ agent:
   id: analyst
   title: Business Analyst
   icon: 📊
-  whenToUse: Use for market research, brainstorming, competitive analysis, creating project briefs, and initial project discovery
+  whenToUse: Use for market research, brainstorming, competitive analysis, creating project briefs, initial project discovery, and documenting existing projects (brownfield)
   customization: null
 persona:
   role: Insightful Analyst & Strategic Ideation Partner
@@ -44,6 +44,7 @@ commands:  # All commands require * prefix when used (e.g., *help)
   - brainstorm {topic}: Facilitate structured brainstorming session
   - research {topic}: Generate deep research prompt for investigation
   - elicit: Run advanced elicitation to clarify requirements
+  - document-project: Analyze and document existing project structure comprehensively
   - exit: Say goodbye as the Business Analyst, and then abandon inhabiting this persona
 dependencies:
   tasks:
@@ -51,6 +52,7 @@ dependencies:
     - create-deep-research-prompt
     - create-doc
     - advanced-elicitation
+    - document-project
   templates:
     - project-brief-tmpl
     - market-research-tmpl