Rename rbos → redbear everywhere, add redbear-info system tool

Replace all 'rbos'/'RBOS' references with 'redbear'/'Red Bear OS'
across the build system, scripts, docs, and configs. Renamed files:
  rbos.ipxe → redbear.ipxe
  assets/rbos-icon.png → assets/redbear-icon.png
  recipes/system/rbos-info → recipes/system/redbear-info

Added redbear-info: a system tool that enumerates all Red Bear OS
custom components, checks runtime availability via scheme paths and
binary presence, and prints status/test info. Supports --verbose,
--json, and --test output modes. Zero external dependencies.

build.sh

@@ -36,7 +36,7 @@ usage()
     echo "               config/ARCH/CONFIG.toml"
     echo "               If you specify both CONFIG and FILESYSTEM_CONFIG, it is not"
     echo "               necessary that they match, but it is recommended."
-    echo "    Examples:  ./build.sh -c demo live - make build/x86_64/demo/rbos-live.iso"
+    echo "    Examples:  ./build.sh -c demo live - make build/x86_64/demo/redbear-live.iso"
     echo "               ./build.sh -6 qemu - make build/i686/desktop/harddrive.img and"
     echo "                                    and run it in qemu"
     echo "    NOTE:      If you do not change ARCH or CONFIG very often, edit mk/config.mk"