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.

scripts/ventoy.sh

@@ -24,9 +24,9 @@ for ARCH in "${ARCHS[@]}"
 do
     for CONFIG_NAME in "${CONFIGS[@]}"
     do
-        IMAGE="build/${ARCH}/${CONFIG_NAME}/rbos-live.iso"
+        IMAGE="build/${ARCH}/${CONFIG_NAME}/redbear-live.iso"
         make ARCH="${ARCH}" CONFIG_NAME="${CONFIG_NAME}" "${IMAGE}"
-        cp -v "${IMAGE}" "${VENTOY}/rbos-${CONFIG_NAME}-${ARCH}.iso"
+        cp -v "${IMAGE}" "${VENTOY}/redbear-${CONFIG_NAME}-${ARCH}.iso"
     done
 done