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.

local/scripts/build-amd.sh

@@ -71,7 +71,7 @@ else
 fi
 
 # Step 3: Build
-echo ">>> Building RBOS with config: $CONFIG"
+echo ">>> Building Red Bear OS with config: $CONFIG"
 echo ">>> This may take 30-60 minutes on first build..."
 CI=1 make all "CONFIG_NAME=$CONFIG" "JOBS=$JOBS"