Remove local development README and enhance scripts for cross-platform compatibility

- Deleted `README.md` for local development setup as it was deemed unnecessary.
- Updated `setup-neon.sh`, `start-all.sh`, and `create-service.sh` scripts to source an OS helper for improved cross-platform command execution.
- Modified commands in `init-project.sh` to reflect the new script structure for starting services.

scripts/db/setup-neon.sh

@@ -5,6 +5,9 @@ set -e
 echo "🚀 Neon Database Setup Script"
 echo ""
 
+# Source OS helper
+source "$(dirname "$0")/../utils/os-helper.sh"
+
 # Colors for output
 GREEN='\033[0;32m'
 YELLOW='\033[1;33m'
@@ -40,8 +43,7 @@ if [ -n "$dev_url" ]; then
     # EN: Update .env.local with new URL
     # VI: Cập nhật .env.local với URL mới
     if grep -q "DATABASE_URL=" "$ENV_LOCAL"; then
-        sed -i.bak "s|DATABASE_URL=.*|DATABASE_URL=$dev_url|" "$ENV_LOCAL"
-        rm -f "${ENV_LOCAL}.bak"
+        run_sed "s|DATABASE_URL=.*|DATABASE_URL=$dev_url|" "$ENV_LOCAL"
     else
         echo "DATABASE_URL=$dev_url" >> "$ENV_LOCAL"
     fi