fix: production deployment issues with Traefik and database migrations

- Add missing created_at column to email_queue table
- Fix 502 Bad Gateway errors with proper Traefik routing configuration
- Create docker-compose.traefik.yml for external Traefik deployment
- Fix health check endpoint path for API path stripping
- Add PostgreSQL init script for Umami database creation
- Add comprehensive deployment guide for Traefik setup

The backend now properly handles /api prefix stripping by Traefik and
migrations run safely in production environments with existing schemas.

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

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

backend/audit-backend.json

@@ -0,0 +1,22 @@
+{
+  "auditReportVersion": 2,
+  "vulnerabilities": {},
+  "metadata": {
+    "vulnerabilities": {
+      "info": 0,
+      "low": 0,
+      "moderate": 0,
+      "high": 0,
+      "critical": 0,
+      "total": 0
+    },
+    "dependencies": {
+      "prod": 329,
+      "dev": 307,
+      "optional": 54,
+      "peer": 1,
+      "peerOptional": 0,
+      "total": 690
+    }
+  }
+}

backend/migrations/018_add_created_at_to_email_queue.js

@@ -0,0 +1,23 @@
+exports.up = async function(knex) {
+  // Check if created_at column already exists
+  const hasCreatedAt = await knex.schema.hasColumn('email_queue', 'created_at');
+  
+  if (!hasCreatedAt) {
+    await knex.schema.table('email_queue', (table) => {
+      table.datetime('created_at').defaultTo(knex.fn.now());
+    });
+    
+    // Update existing rows to have a created_at value based on scheduled_at
+    await knex('email_queue')
+      .whereNull('created_at')
+      .update({
+        created_at: knex.ref('scheduled_at')
+      });
+  }
+};
+
+exports.down = async function(knex) {
+  await knex.schema.table('email_queue', (table) => {
+    table.dropColumn('created_at');
+  });
+};

backend/server.js

@@ -10,7 +10,7 @@ const cors = require('cors');
 const rateLimit = require('express-rate-limit');
 const jwt = require('jsonwebtoken');
 const path = require('path');
-const { initializeDatabase } = require('./src/database/db');
+const { initializeDatabase, db } = require('./src/database/db');
 const { startFileWatcher } = require('./src/services/fileWatcher');
 const { startExpirationChecker } = require('./src/services/expirationChecker');
 const { initializeTransporter, startEmailQueueProcessor } = require('./src/services/emailProcessor');
@@ -152,7 +152,7 @@ app.use('/thumbnails', require('./src/middleware/photoAuth'), setCorsHeaders, se
 app.use('/uploads', setCorsHeaders, secureStatic(path.join(__dirname, 'storage/uploads')));
 
 // Health check endpoint
-app.get('/api/health', async (req, res) => {
+app.get('/health', async (req, res) => {
   try {
     // Check database connectivity
     await db.raw('SELECT 1');