feat: Implement complete Zero OS Alpine Initramfs Builder

- Complete bash framework with strict error handling
- Modular library system (docker, alpine, components, initramfs, kernel, testing)
- Rust component integration (zinit, rfs, mycelium) with musl targeting
- Rootless Docker/Podman support for GitHub Actions
- Centralized configuration in config/build.conf
- 2-stage module loading system
- Strip + UPX optimization for minimal size
- Complete zinit integration replacing OpenRC
- GitHub Actions CI/CD pipeline
- Comprehensive documentation and usage guides

Components:
- Latest stable kernel 6.12.44
- Alpine Linux 3.22 base
- ThreeFold components: zinit, mycelium, rfs, corex
- Target: ~8-12MB final initramfs.cpio.xz

configs/zinit/mycelium.yaml

@@ -0,0 +1,6 @@
+exec: /usr/bin/mycelium --key-file /tmp/mycelium_priv_key.bin
+  --tun-name my0 --silent --peers tcp://188.40.132.242:9651 tcp://136.243.47.186:9651
+  tcp://185.69.166.7:9651 tcp://185.69.166.8:9651 tcp://65.21.231.58:9651 tcp://65.109.18.113:9651
+  tcp://209.159.146.190:9651 tcp://5.78.122.16:9651 tcp://5.223.43.251:9651 tcp://142.93.217.194:9651
+after:
+  - network