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/workflow_management/n8n-validate-workflow.ts

@@ -0,0 +1,71 @@
+import { ToolDocumentation } from '../types';
+
+export const n8nValidateWorkflowDoc: ToolDocumentation = {
+  name: 'n8n_validate_workflow',
+  category: 'workflow_management',
+  essentials: {
+    description: 'Validate workflow from n8n instance by ID - checks nodes, connections, expressions, and returns errors/warnings',
+    keyParameters: ['id'],
+    example: 'n8n_validate_workflow({id: "wf_abc123"})',
+    performance: 'Network-dependent (100-500ms) - fetches and validates workflow',
+    tips: [
+      'Use options.profile to control validation strictness (minimal/runtime/ai-friendly/strict)',
+      'Validation includes node configs, connections, and n8n expression syntax',
+      'Returns categorized errors, warnings, and actionable fix suggestions'
+    ]
+  },
+  full: {
+    description: `Validates a workflow stored in your n8n instance by fetching it via API and running comprehensive validation checks. This tool:
+
+- Fetches the workflow from n8n using the workflow ID
+- Validates all node configurations based on their schemas
+- Checks workflow connections and data flow
+- Validates n8n expression syntax in all fields
+- Returns categorized issues with fix suggestions
+
+The validation uses the same engine as validate_workflow but works with workflows already in n8n, making it perfect for validating existing workflows before execution.
+
+Requires N8N_API_URL and N8N_API_KEY environment variables to be configured.`,
+    parameters: {
+      id: {
+        type: 'string',
+        required: true,
+        description: 'The workflow ID to validate from your n8n instance'
+      },
+      options: {
+        type: 'object',
+        required: false,
+        description: 'Validation options: {validateNodes: bool (default true), validateConnections: bool (default true), validateExpressions: bool (default true), profile: "minimal"|"runtime"|"ai-friendly"|"strict" (default "runtime")}'
+      }
+    },
+    returns: 'ValidationResult object containing isValid boolean, arrays of errors/warnings, and suggestions for fixes',
+    examples: [
+      'n8n_validate_workflow({id: "wf_abc123"}) - Validate with default settings',
+      'n8n_validate_workflow({id: "wf_abc123", options: {profile: "strict"}}) - Strict validation',
+      'n8n_validate_workflow({id: "wf_abc123", options: {validateExpressions: false}}) - Skip expression validation'
+    ],
+    useCases: [
+      'Validating workflows before running them in production',
+      'Checking imported workflows for compatibility',
+      'Debugging workflow execution failures',
+      'Ensuring workflows follow best practices',
+      'Pre-deployment validation in CI/CD pipelines'
+    ],
+    performance: 'Depends on workflow size and API latency. Typically 100-500ms for medium workflows.',
+    bestPractices: [
+      'Run validation before activating workflows in production',
+      'Use "runtime" profile for pre-execution checks',
+      'Use "strict" profile for code review and best practices',
+      'Fix errors before warnings - errors will likely cause execution failures',
+      'Pay attention to expression validation - syntax errors are common'
+    ],
+    pitfalls: [
+      'Requires valid API credentials - check n8n_health_check first',
+      'Large workflows may take longer to validate',
+      'Some warnings may be intentional (e.g., optional parameters)',
+      'Profile affects validation time - strict is slower but more thorough',
+      'Expression validation may flag working but non-standard syntax'
+    ],
+    relatedTools: ['validate_workflow', 'n8n_get_workflow', 'validate_workflow_expressions', 'n8n_health_check']
+  }
+};