feat: implement anonymous telemetry system with Supabase integration

Adds zero-configuration anonymous usage statistics to track:
- Number of active users with deterministic user IDs
- Which MCP tools AI agents use most
- What workflows are built (sanitized to protect privacy)
- Common errors and issues

Key features:
- Zero-configuration design with hardcoded write-only credentials
- Privacy-first approach with comprehensive data sanitization
- Opt-out support via config file and environment variables
- Docker-friendly with environment variable support
- Multi-process safe with immediate flush strategy
- Row Level Security (RLS) policies for write-only access

Technical implementation:
- Supabase backend with anon key for INSERT-only operations
- Workflow sanitization removes all sensitive data
- Environment variables checked for opt-out (TELEMETRY_DISABLED, etc.)
- Telemetry enabled by default but respects user preferences
- Cleaned up all debug logging for production readiness

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

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

scripts/test-workflow-insert.ts

@@ -0,0 +1,55 @@
+#!/usr/bin/env npx tsx
+/**
+ * Test direct workflow insert to Supabase
+ */
+
+import { createClient } from '@supabase/supabase-js';
+
+const TELEMETRY_BACKEND = {
+  URL: 'https://ydyufsohxdfpopqbubwk.supabase.co',
+  ANON_KEY: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6InlkeXVmc29oeGRmcG9wcWJ1YndrIiwicm9sZSI6ImFub24iLCJpYXQiOjE3NTg3OTYyMDAsImV4cCI6MjA3NDM3MjIwMH0.xESphg6h5ozaDsm4Vla3QnDJGc6Nc_cpfoqTHRynkCk'
+};
+
+async function testWorkflowInsert() {
+  const supabase = createClient(TELEMETRY_BACKEND.URL, TELEMETRY_BACKEND.ANON_KEY, {
+    auth: {
+      persistSession: false,
+      autoRefreshToken: false,
+    }
+  });
+
+  const testWorkflow = {
+    user_id: 'direct-test-' + Date.now(),
+    workflow_hash: 'hash-direct-' + Date.now(),
+    node_count: 2,
+    node_types: ['webhook', 'http'],
+    has_trigger: true,
+    has_webhook: true,
+    complexity: 'simple' as const,
+    sanitized_workflow: {
+      nodes: [
+        { id: '1', type: 'webhook', parameters: {} },
+        { id: '2', type: 'http', parameters: {} }
+      ],
+      connections: {}
+    }
+  };
+
+  console.log('Attempting direct insert to telemetry_workflows...');
+  console.log('Data:', JSON.stringify(testWorkflow, null, 2));
+
+  const { data, error } = await supabase
+    .from('telemetry_workflows')
+    .insert([testWorkflow]);
+
+  if (error) {
+    console.error('\n❌ Error:', error);
+  } else {
+    console.log('\n✅ Success! Workflow inserted');
+    if (data) {
+      console.log('Response:', data);
+    }
+  }
+}
+
+testWorkflowInsert().catch(console.error);