Enhance README and RPC for package management

- Added instructions to README.md for building an ISO from source and flashing it to USB.
- Introduced a new RPC method for package installation, including security checks and container management.
- Updated Docker and Podman integration in build scripts to support both container runtimes.
- Enhanced Nginx configuration for improved timeout settings and WebSocket support.
- Added new app metadata for additional applications in the Docker package scanner.

README.md

@@ -44,6 +44,18 @@
 
 ## 🚀 Quick Start
 
+### Build ISO from Source
+
+```bash
+# One command to build everything and create flashable ISO
+./build-iso-complete.sh --remote archipelago@192.168.1.228
+
+# Flash to USB
+./flash-to-usb.sh /dev/diskN
+```
+
+**📘 See [BUILD-GUIDE.md](BUILD-GUIDE.md) for detailed build instructions.**
+
 ### Prerequisites
 - macOS 10.15 (Catalina) or later
 - 8GB RAM minimum (16GB recommended)