docs: comprehensive documentation overhaul for v2.2.3

Major documentation update bringing all docs current with the 122-tool,
16-category state of the project (previously frozen at v2.1.0-alpha/59 tools).

New documentation (9 files):
- FREEROUTING_GUIDE.md - autorouter setup, Docker/Podman, all 4 tools
- SCHEMATIC_TOOLS_REFERENCE.md - all 27 schematic tools with parameters
- ROUTING_TOOLS_REFERENCE.md - all 13 routing tools with examples
- FOOTPRINT_SYMBOL_CREATOR_GUIDE.md - 8 creator tools with examples
- SVG_IMPORT_GUIDE.md - SVG logo import tool
- DATASHEET_TOOLS_GUIDE.md - datasheet enrichment tools
- PCB_DESIGN_WORKFLOW.md - end-to-end design guide
- ARCHITECTURE.md - system architecture for contributors
- INDEX.md - documentation table of contents

Updated documentation (12 files):
- README.md - tool count 64->122, feature list, contributor credits
- TOOL_INVENTORY.md - complete rebuild with all 122 tools
- STATUS_SUMMARY.md - updated to v2.2.3 feature matrix
- ROADMAP.md - marked completed milestones, added v2.3+ vision
- KNOWN_ISSUES.md - removed resolved issues, added v2.2.x fixes
- CLIENT_CONFIGURATION.md - added KICAD_MCP_DEV, FREEROUTING_JAR env vars
- LIBRARY_INTEGRATION.md - added symbol and project-local library support
- ROUTER_ARCHITECTURE.md, ROUTER_QUICK_START.md - updated tool counts
- IPC_BACKEND_STATUS.md - updated dates
- JLCPCB_USAGE_GUIDE.md - added cross-reference note
- CONTRIBUTING.md - added ARCHITECTURE.md reference, updated tool count

Archived 10 completed planning docs to docs/archive/.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CONTRIBUTING.md

@@ -6,6 +6,7 @@ Thank you for your interest in contributing to the KiCAD MCP Server! This guide
 
 - [Development Environment Setup](#development-environment-setup)
 - [Project Structure](#project-structure)
+- [Architecture Overview](#architecture-overview)
 - [Development Workflow](#development-workflow)
 - [Testing](#testing)
 - [Code Style](#code-style)
@@ -144,6 +145,22 @@ kicad-mcp-server/
 
 ---
 
+## Architecture Overview
+
+The KiCAD MCP Server is organized into several key components:
+
+- **TypeScript MCP Server** (`src/`) - Handles MCP protocol communication and tool routing
+- **Python KiCAD Interface** (`python/`) - Interfaces with KiCAD's Python API (pcbnew)
+- **Tool Router** - Organizes 122+ tools into 8 discoverable categories
+- **Resource System** - Provides dynamic project/board state information
+- **Prompt System** - Offers context-aware design prompts
+
+**Current Tool Count:** 122+ tools across 8 categories (direct + routed)
+
+For detailed architecture information, see `docs/ROUTER_ARCHITECTURE.md`.
+
+---
+
 ## Development Workflow
 
 ### 1. Create a Feature Branch