feat: add canonical AI tool examples for search_nodes includeExamples

Phase 3 Complete: AI Examples Extraction and Enhancement

Created canonical examples for 4 critical AI tools that were missing from
the template database. These hand-crafted examples demonstrate best practices
from FINAL_AI_VALIDATION_SPEC.md and are now available via includeExamples parameter.

New Files:
1. **src/data/canonical-ai-tool-examples.json** (11 examples)
   - HTTP Request Tool: 3 examples (Weather API, GitHub Issues, Slack)
   - Code Tool: 3 examples (Shipping calc, Data formatting, Date parsing)
   - AI Agent Tool: 2 examples (Research specialist, Data analyst)
   - MCP Client Tool: 3 examples (Filesystem, Puppeteer, Database)

2. **src/scripts/seed-canonical-ai-examples.ts**
   - Automated seeding script for canonical examples
   - Creates placeholder template (ID: -1000) for foreign key constraint
   - Properly tracks complexity, credentials, and expressions
   - Logs seeding progress with detailed metadata

Example Features:
- All examples follow validation spec requirements
- Include proper toolDescription/description fields
- Demonstrate credential configuration
- Show n8n expression usage
- Cover simple, medium, and complex use cases
- Provide real-world context and use cases

Database Impact:
- Before: 197 node configs from 10 templates
- After: 208 node configs (11 canonical + 197 template)
- Critical gaps filled for most-used AI tools

Usage:
```typescript
// Via search_nodes
search_nodes({query: "HTTP Request Tool", includeExamples: true})

// Via get_node_essentials
get_node_essentials({
  nodeType: "nodes-langchain.toolCode",
  includeExamples: true
})
```

Benefits:
- Users get immediate working examples for AI tools
- Examples demonstrate validation best practices
- Reduces trial-and-error in AI workflow construction
- Provides templates for common AI integration patterns

Files Changed:
- src/data/canonical-ai-tool-examples.json (NEW)
- src/scripts/seed-canonical-ai-examples.ts (NEW)

Database: ✅ Examples seeded successfully (11 entries)
Build Status: ✅ TypeScript compiles cleanly

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

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

src/scripts/seed-canonical-ai-examples.ts

@@ -0,0 +1,161 @@
+#!/usr/bin/env node
+/**
+ * Seed canonical AI tool examples into the database
+ *
+ * These hand-crafted examples demonstrate best practices for critical AI tools
+ * that are missing from the template database.
+ */
+
+import * as fs from 'fs';
+import * as path from 'path';
+import { createDatabaseAdapter } from '../database/database-adapter';
+import { logger } from '../utils/logger';
+
+interface CanonicalExample {
+  name: string;
+  use_case: string;
+  complexity: 'simple' | 'medium' | 'complex';
+  parameters: Record<string, any>;
+  credentials?: Record<string, any>;
+  connections?: Record<string, any>;
+  notes: string;
+}
+
+interface CanonicalToolExamples {
+  node_type: string;
+  display_name: string;
+  examples: CanonicalExample[];
+}
+
+interface CanonicalExamplesFile {
+  description: string;
+  version: string;
+  examples: CanonicalToolExamples[];
+}
+
+async function seedCanonicalExamples() {
+  try {
+    // Load canonical examples file
+    const examplesPath = path.join(__dirname, '../data/canonical-ai-tool-examples.json');
+    const examplesData = fs.readFileSync(examplesPath, 'utf-8');
+    const canonicalExamples: CanonicalExamplesFile = JSON.parse(examplesData);
+
+    logger.info('Loading canonical AI tool examples', {
+      version: canonicalExamples.version,
+      tools: canonicalExamples.examples.length
+    });
+
+    // Initialize database
+    const db = await createDatabaseAdapter('./data/nodes.db');
+
+    // First, ensure we have placeholder templates for canonical examples
+    const templateStmt = db.prepare(`
+      INSERT OR IGNORE INTO templates (
+        id,
+        workflow_id,
+        name,
+        description,
+        views,
+        created_at,
+        updated_at
+      ) VALUES (?, ?, ?, ?, ?, datetime('now'), datetime('now'))
+    `);
+
+    // Create one placeholder template for canonical examples
+    const canonicalTemplateId = -1000;
+    templateStmt.run(
+      canonicalTemplateId,
+      canonicalTemplateId, // workflow_id must be unique
+      'Canonical AI Tool Examples',
+      'Hand-crafted examples demonstrating best practices for AI tools',
+      99999 // High view count
+    );
+
+    // Prepare insert statement for node configs
+    const stmt = db.prepare(`
+      INSERT OR REPLACE INTO template_node_configs (
+        node_type,
+        template_id,
+        template_name,
+        template_views,
+        node_name,
+        parameters_json,
+        credentials_json,
+        has_credentials,
+        has_expressions,
+        complexity,
+        use_cases
+      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+    `);
+
+    let totalInserted = 0;
+
+    // Seed each tool's examples
+    for (const toolExamples of canonicalExamples.examples) {
+      const { node_type, display_name, examples } = toolExamples;
+
+      logger.info(`Seeding examples for ${display_name}`, {
+        nodeType: node_type,
+        exampleCount: examples.length
+      });
+
+      for (let i = 0; i < examples.length; i++) {
+        const example = examples[i];
+
+        // All canonical examples use the same template ID
+        const templateId = canonicalTemplateId;
+        const templateName = `Canonical: ${display_name} - ${example.name}`;
+
+        // Check for expressions in parameters
+        const paramsStr = JSON.stringify(example.parameters);
+        const hasExpressions = paramsStr.includes('={{') || paramsStr.includes('$json') || paramsStr.includes('$node') ? 1 : 0;
+
+        // Insert into database
+        stmt.run(
+          node_type,
+          templateId,
+          templateName,
+          99999, // High view count for canonical examples
+          example.name,
+          JSON.stringify(example.parameters),
+          example.credentials ? JSON.stringify(example.credentials) : null,
+          example.credentials ? 1 : 0,
+          hasExpressions,
+          example.complexity,
+          example.use_case
+        );
+
+        totalInserted++;
+        logger.info(`  ✓ Seeded: ${example.name}`, {
+          complexity: example.complexity,
+          hasCredentials: !!example.credentials,
+          hasExpressions: hasExpressions === 1
+        });
+      }
+    }
+
+    db.close();
+
+    logger.info('Canonical examples seeding complete', {
+      totalExamples: totalInserted,
+      tools: canonicalExamples.examples.length
+    });
+
+    console.log('\n✅ Successfully seeded', totalInserted, 'canonical AI tool examples');
+    console.log('\nExamples are now available via:');
+    console.log('  • search_nodes({query: "HTTP Request Tool", includeExamples: true})');
+    console.log('  • get_node_essentials({nodeType: "nodes-langchain.toolCode", includeExamples: true})');
+
+  } catch (error) {
+    logger.error('Failed to seed canonical examples', { error });
+    console.error('❌ Error:', error);
+    process.exit(1);
+  }
+}
+
+// Run if called directly
+if (require.main === module) {
+  seedCanonicalExamples().catch(console.error);
+}
+
+export { seedCanonicalExamples };