feat: complete modular documentation system for all MCP tools (#60)

- Migrated all 40 MCP tools documentation to modular structure
- Created comprehensive documentation with both essentials and full details
- Organized tools by category: discovery, configuration, validation, templates, workflow_management, system, special
- Fixed all TODO placeholders with informative, precise content
- Each tool now has concise description, key tips, and full documentation
- Improved documentation quality: 30-40% more concise while maintaining usefulness
- Fixed TypeScript compilation issues and removed orphaned content
- All tools accessible via tools_documentation MCP endpoint
- Build successful with zero errors

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

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

src/mcp/tool-docs/discovery/list-ai-tools.ts

@@ -0,0 +1,24 @@
+import { ToolDocumentation } from '../types';
+
+export const listAiToolsDoc: ToolDocumentation = {
+  name: 'list_ai_tools',
+  category: 'discovery',
+  essentials: {
+    description: 'List AI-optimized nodes. Note: ANY node can be AI tool! Connect any node to AI Agent\'s tool port. Community nodes need N8N_COMMUNITY_PACKAGES_ALLOW_TOOL_USAGE=true.',
+    keyParameters: [],
+    example: 'list_ai_tools()',
+    performance: 'Fast query',
+    tips: ['ANY node works as AI tool']
+  },
+  full: {
+    description: 'List nodes marked as AI tools. IMPORTANT: Any n8n node can be used as AI tool by connecting to AI Agent\'s tool port.',
+    parameters: {},
+    returns: 'Array of AI-optimized nodes with usage hints',
+    examples: ['list_ai_tools() - Get AI-optimized nodes'],
+    useCases: ['Find AI model integrations', 'Build agent toolchains'],
+    performance: 'Fast query, cached results',
+    bestPractices: ['Any node works as tool', 'Community nodes need env var'],
+    pitfalls: ['List not exhaustive - all nodes work'],
+    relatedTools: ['get_node_as_tool_info', 'search_nodes']
+  }
+};