perf: Comprehensive efficiency optimizations

Implemented all 5 critical efficiency improvements to optimize
performance, reduce resource usage, and improve scalability.

## 1. Database Indexes
- Added indexes on sermon_notes foreign keys (user_id, sermon_id)
- Added composite index on sermons (archived, date DESC)
- Added indexes on frequently queried columns across all tables
- Impact: Faster queries as data grows, better JOIN performance

## 2. Eliminated N+1 Query Pattern
- Reduced 2 API calls to 1 on home page load
- Changed from separate active/archived fetches to single call
- Filter archived sermons client-side using computed properties
- Impact: 50% reduction in HTTP requests per page load

## 3. Scheduled Database Cleanup
- Extended existing plugin to clean expired sessions hourly
- Added cleanup for expired rate limits every hour
- Added cleanup for expired password reset codes every hour
- Sermon cleanup continues to run daily based on retention policy
- Impact: Prevents database table growth, better performance

## 4. Multi-stage Docker Build
- Implemented 3-stage build: deps -> builder -> runtime
- Separated build-time and runtime dependencies
- Added non-root user (nuxt:nodejs) for security
- Integrated dumb-init for proper signal handling
- Added health check endpoint at /api/health
- Impact: Smaller image size, faster deployments, better security

## 5. HTTP Caching
- Static assets: 1 year cache (immutable)
- Logos/images: 1 year cache (immutable)
- API routes: No cache (always fresh)
- HTML pages: 10 minute cache with revalidation
- Impact: Reduced bandwidth, faster page loads, less server load

All optimizations follow best practices and maintain backward
compatibility with existing functionality.

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

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

nuxt.config.ts

@@ -2,7 +2,7 @@
 export default defineNuxtConfig({
   compatibilityDate: '2024-04-03',
   devtools: { enabled: true },
-  
+
   modules: [
     '@nuxtjs/tailwindcss'
   ],
@@ -26,6 +26,19 @@ export default defineNuxtConfig({
 
   css: ['~/assets/css/main.css'],
 
+  // Configure route caching rules
+  routeRules: {
+    // Static assets - cache for 1 year (immutable)
+    '/_nuxt/**': { headers: { 'cache-control': 'public, max-age=31536000, immutable' } },
+    '/logos/**': { headers: { 'cache-control': 'public, max-age=31536000, immutable' } },
+
+    // API routes - no cache
+    '/api/**': { headers: { 'cache-control': 'no-store, no-cache, must-revalidate' } },
+
+    // HTML pages - cache for 10 minutes with revalidation
+    '/**': { headers: { 'cache-control': 'public, max-age=600, must-revalidate' } }
+  },
+
   runtimeConfig: {
     // Private runtime config (server-side only)
     // These are automatically overridden by NUXT_<KEY> environment variables