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.

mk/qemu.mk

@@ -158,7 +158,7 @@ ifneq ($(QEMU_KERNEL),)
 endif
 
 ifeq ($(live),yes)
-	DISK=$(BUILD)/rbos-live.iso
+	DISK=$(BUILD)/redbear-live.iso
 else
 	DISK=$(BUILD)/harddrive.img
 endif
@@ -212,7 +212,7 @@ else
 
 	EXTRANETARGS=
 	ifeq ($(netboot),yes)
-		EXTRANETARGS+=,tftp=$(BUILD),bootfile=rbos.ipxe
+		EXTRANETARGS+=,tftp=$(BUILD),bootfile=redbear.ipxe
 		QEMUFLAGS+=-kernel /usr/lib/ipxe/ipxe-amd64.efi
 	endif