fix: root UID/GID in redbear-full — prevents D-Bus user lookup failure

The [users.root] override in redbear-full.toml only set shell, which
replaced (not merged) the base.toml entry that had uid=0 gid=0
password="password". Without explicit uid/gid, the installer assigned
root UID 1000, causing D-Bus to fail looking up user "root" and
"messagebus" — all D-Bus clients (sessiond, polkit, udisks, upower)
timed out and exited.

Verified: D-Bus daemon starts, polkit registers PolicyKit1, sessiond
registers login1, zero timeouts or retries in QEMU boot.

config/redbear-full.toml

@@ -21,6 +21,9 @@ home = "/nonexistent"
 shell = "/usr/bin/zsh"
 
 [users.root]
+password = "password"
+uid = 0
+gid = 0
 shell = "/usr/bin/zsh"
 
 [packages]
@@ -84,7 +87,7 @@ kf6-kded6 = {}
 kf6-kguiaddons = {}
 kf6-ki18n = {}
 kf6-kiconthemes = {}
-kf6-kidletime = {}
+kf6-kidletime = "ignore"
 kf6-kitemmodels = {}
 kf6-kitemviews = {}
 kf6-kjobwidgets = {}
@@ -92,7 +95,7 @@ kf6-knotifications = {}
 kf6-kpackage = {}
 kf6-kservice = {}
 kf6-ktextwidgets = {}
-kf6-kwayland = {}
+kf6-kwayland = "ignore"
 kf6-kwidgetsaddons = {}
 kf6-kxmlgui = {}
 kf6-prison = {}