feat(mcp): add dev_map tool for codebase overview

[prosdev]

Summary

Implements #81 - Codebase Map (dev_map)

Adds a new MCP tool that returns a high-level overview of the codebase structure. When an AI asks "what does this codebase do?" or "show me the architecture", this tool provides a navigable map of directories, modules, and public APIs.

Changes

Core Map Module (packages/core/src/map/)

• types.ts: MapNode, ExportInfo, MapOptions, CodebaseMap types
• index.ts: generateCodebaseMap() and formatCodebaseMap() functions

Features:

• Builds directory tree from indexed documents
• Counts components per directory (recursive)
• Extracts exported symbols
• Configurable depth (1-5 levels)
• Focus on specific directory
• Token budget with automatic depth reduction
• Alphabetical sorting

MCP Adapter (packages/mcp-server/src/adapters/built-in/map-adapter.ts)

• dev_map tool with parameters:
  • depth: Directory depth (1-5, default: 2)
  • focus: Focus on specific directory path
  • includeExports: Show exported symbols (default: true)
  • tokenBudget: Max tokens for output (default: 2000)

Example Output

# Codebase Map

└── root/ (195 components)
    └── packages/ (150 components)
        ├── core/ (45 components)
        │   └── exports: RepositoryIndexer, VectorStorage, TypeScriptScanner...
        ├── cli/ (12 components)
        │   └── exports: createCLI, indexCommand, mcpCommand...
        ├── mcp-server/ (28 components)
        │   └── exports: MCPServer, SearchAdapter, PlanAdapter...
        └── subagents/ (18 components)
            └── exports: PlannerAgent, ExplorerAgent, Coordinator...

**Total:** 195 indexed components across 15 directories

Testing

• 17 new tests for map generation in core
• 22 new tests for MapAdapter
• All 1359 tests passing

Closes #81