Update paths for config/ directory structure

Adjusted all references to match new config/ structure:
- docker/config/nginx/default.conf → config/nginx/default.conf
- docker/init.sql → config/docker/init.sql
- docker/start.sh → config/docker/start.sh

Updated files:
- docker-compose.yml: Updated volume mount paths
- README.md: Updated project structure documentation

New structure consolidates all configuration files under config/
for better organization and clarity.

Tested and verified all services running correctly.

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

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

config/docker/start.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+# Start PHP-FPM
+php-fpm -D
+
+# Start Nginx in foreground
+nginx -g 'daemon off;'