docs: restructure documentation for improved clarity and navigation

Reorganize documentation into user-focused, developer-focused, and deployment-focused sections.

**New structure:**
- Root: README.md (streamlined), QUICK_START.md, API_REFERENCE.md
- docs/user-guide/: configuration, API usage, integrations, troubleshooting
- docs/developer/: contributing, development setup, testing, architecture
- docs/deployment/: Docker deployment, production checklist, monitoring
- docs/reference/: environment variables, MCP tools, data formats

**Changes:**
- Streamline README.md from 831 to 469 lines
- Create QUICK_START.md for 5-minute onboarding
- Create API_REFERENCE.md as single source of truth for API
- Remove 9 outdated specification docs (v0.2.0 API design)
- Remove DOCKER_API.md (content consolidated into new structure)
- Remove docs/plans/ directory with old design documents
- Update CLAUDE.md with documentation structure guide
- Remove orchestration-specific references

**Benefits:**
- Clear entry points for different audiences
- No content duplication
- Better discoverability through logical hierarchy
- All content reflects current v0.3.0 API

ROADMAP.md

@@ -66,6 +66,18 @@ This document outlines planned features and improvements for the AI-Trader proje
     - Chart library (Plotly.js, Chart.js, or Recharts)
     - Served alongside API (single container deployment)
 
+#### Development Infrastructure
+- **Migration to uv Package Manager** - Modern Python package management
+  - Replace pip with uv for dependency management
+  - Create pyproject.toml with project metadata and dependencies
+  - Update Dockerfile to use uv for faster, more reliable builds
+  - Update development documentation and workflows
+  - Benefits:
+    - 10-100x faster dependency resolution and installation
+    - Better dependency locking and reproducibility
+    - Unified tool for virtual environments and package management
+    - Drop-in pip replacement with improved UX
+
 ## Contributing
 
 We welcome contributions to any of these planned features! Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.