Add comprehensive documentation, recipes, and testing framework

- Add extensive documentation covering current status, usage, and testing strategies
- Add recipe files for various image configurations (minimal, debug, kernel test, etc.)
- Add testing and management scripts for comprehensive testing workflows
- Add Go module configuration and updated Go code
- Add manual bootable image creation script
- Update todo with current project status and next steps

recipes/minimal-test-with-bootloader.yml

@@ -0,0 +1,29 @@
+name: minimal-test-with-bootloader
+description: Test recipe using existing rootfs with bootloader files
+base-image: debian:trixie-slim
+image-version: "0.1"
+
+stages:
+  - type: org.osbuild.debian.apt
+    options:
+      packages:
+        - bash
+        - coreutils
+        - linux-image-amd64
+        - initramfs-tools
+        - grub-pc
+      update: true
+      clean: true
+
+output:
+  formats: ["raw"]
+  size: "2G"
+  path: "minimal-test-with-bootloader"
+
+metadata:
+  author: "particle-os"
+  category: "test"
+  tags: ["test", "minimal", "particle-os", "bootloader"]
+  description: "Minimal test recipe with bootloader support"
+  target_audience: "Developers testing bootloader fixes"
+  based_on: "debian:trixie-slim"