Update documentation to reflect Phase 3 refactoring completion

Updated ARCHITECTURE.md:
- Changed govmap.py section to govmap/ package section
- Updated architecture diagram to show modular package structure
- Marked Phase 3 as completed (✅)
- Listed all package modules and their responsibilities

Updated CLAUDE.md:
- Updated Business Logic Layer description with package structure
- Updated Key Files section with new modular package details
- Updated development roadmap to show Phase 3 as complete
- Updated "Adding New API Endpoint Support" instructions
- Updated "Important Notes for AI Agents" with package info
- Changed test count from 27 to 34 tests (all passing)

All documentation now reflects the completed modular refactoring
while emphasizing backward compatibility.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

ARCHITECTURE.md

@@ -58,15 +58,18 @@ All settings (timeouts, retries, rate limits) are configurable via environment v
                              ↓
 ┌─────────────────────────────────────────────────────────────┐
 │                 Business Logic Layer                         │
-│  ┌────────────────────┐  ┌──────────────────────────────┐  │
-│  │ Market Analysis    │  │ Deal Processing & Filtering  │  │
-│  │ (analyze_market    │  │ (_is_same_building, etc.)    │  │
-│  │  _trends logic)    │  │                              │  │
-│  └────────────────────┘  └──────────────────────────────┘  │
-│  ┌────────────────────────────────────────────────────────┐ │
-│  │            govmap.py (GovmapClient)                    │ │
-│  │  • Validation  • Retry Logic  • Rate Limiting         │ │
-│  └─────────────────────────┬──────────────────────────────┘ │
+│  ┌─────────────────────────────────────────────────────────┐ │
+│  │              govmap/ Package                            │ │
+│  │  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐ │ │
+│  │  │ client.py   │  │ validators.py│  │ filters.py    │ │ │
+│  │  │ (API calls) │  │ (validation) │  │ (filtering)   │ │ │
+│  │  └─────────────┘  └──────────────┘  └───────────────┘ │ │
+│  │  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐ │ │
+│  │  │statistics.py│  │market_       │  │ utils.py      │ │ │
+│  │  │ (stats)     │  │analysis.py   │  │ (helpers)     │ │ │
+│  │  └─────────────┘  └──────────────┘  └───────────────┘ │ │
+│  │  • Retry Logic  • Rate Limiting  • Validation        │ │
+│  └─────────────────────────┬───────────────────────────────┘ │
 └───────────────────────────┬┴──────────────────────────────┘
                             │ HTTP/JSON
                             ↓
@@ -111,22 +114,28 @@ custom_config = GovmapConfig(max_retries=5, requests_per_second=10.0)
 set_config(custom_config)
 ```
 
-### API Client Layer (`govmap.py`)
+### API Client Layer (`govmap/` package)
 
-**Purpose:** Communicate with Govmap API with reliability features
+**Purpose:** Modular package for Govmap API interaction and data processing
 
-**Key Components:**
+**Package Structure:**
+- `client.py` - GovmapClient class with API methods
+- `validators.py` - Input validation functions
+- `filters.py` - Deal filtering logic
+- `statistics.py` - Statistical calculations
+- `market_analysis.py` - Market analysis functions
+- `utils.py` - Helper utilities
+- `__init__.py` - Public API exports
 
-#### GovmapClient Class
+#### GovmapClient Class (`govmap/client.py`)
 
 **Responsibilities:**
 - Make HTTP requests to Govmap API
 - Implement retry logic with exponential backoff
 - Enforce rate limiting
-- Validate inputs
-- Parse and validate responses
+- Delegate to specialized modules for validation, filtering, analysis
 
-**Key Methods:**
+**Core API Methods:**
 - `autocomplete_address()` - Search for addresses
 - `get_gush_helka()` - Get block/parcel data
 - `get_deals_by_radius()` - Get nearby deals
@@ -134,10 +143,17 @@ set_config(custom_config)
 - `get_neighborhood_deals()` - Get neighborhood deals
 - `find_recent_deals_for_address()` - Main comprehensive search
 
+**Business Logic Methods** (delegate to respective modules):
+- `filter_deals_by_criteria()` - Filter deals by various criteria
+- `calculate_deal_statistics()` - Calculate statistical metrics
+- `calculate_market_activity_score()` - Analyze market activity
+- `analyze_investment_potential()` - Analyze investment potential
+- `get_market_liquidity()` - Analyze market liquidity
+
 **Reliability Features:**
 1. **Retry Logic** - Exponential backoff on failures
 2. **Rate Limiting** - Tracks request times, enforces delays
-3. **Input Validation** - Validates all inputs before API calls
+3. **Input Validation** - Delegates to validators module
 4. **Timeouts** - Configurable connect and read timeouts
 
 ### MCP Tools Layer (`fastmcp_server.py`)
@@ -371,11 +387,11 @@ GOVMAP_DEFAULT_DEAL_LIMIT=100
 
 ## Future Architecture Evolution
 
-### Phase 3: Package Refactoring (PLANNED)
+### Phase 3: Package Refactoring (✅ COMPLETED)
 
-**See `.cursor/plans/PHASE3-REFACTORING.md` for detailed plan**
+**✅ COMPLETED - See `.cursor/plans/PHASE3-REFACTORING.md` for detailed plan**
 
-Refactor `govmap.py` (1,378 lines) into modular package:
+The monolithic `govmap.py` (1,454 lines) has been refactored into a modular package:
 
 ```
 nadlan_mcp/