Wire evdevd input devices into udev-shim and enable udev in libinput

Phase 3 input chain wiring:

udev-shim: when scheme:evdev is registered (by evdevd), probe for
event0..event7 devices and create /dev/input/eventN nodes pointing to
scheme:evdev/eventN. This bridges evdevd's evdev devices into the
/dev/input namespace that libinput and compositors expect.

libinput: remove -Dudev=false and add libudev-stub as a dependency.
The libudev-stub recipe provides libudev.so that reads from scheme:udev
(udev-shim), giving libinput a working udev enumeration path instead of
stub functions that return NULL.

Input chain is now: hardware → /scheme/input → evdevd → scheme:evdev →
udev-shim → /dev/input/eventN → libudev-stub → libinput → KWin.

recipes/wip/libs/other/libinput/recipe.toml

@@ -1,4 +1,4 @@
-#TODO: needs libevdev working; udev integration is disabled so the compositor owns device discovery
+#TODO: needs libevdev working; udev integration via libudev-stub (scheme:udev)
 [source]
 tar = "https://gitlab.freedesktop.org/libinput/libinput/-/archive/1.30.2/libinput-1.30.2.tar.bz2"
 patches = ["redox.patch"]
@@ -10,9 +10,9 @@ mesonflags = [
     "-Dmtdev=false",
     "-Ddebug-gui=false",
     "-Dtests=false",
-    "-Dudev=false",
     "-Ddocumentation=false",
 ]
 dependencies = [
     "libevdev",
+    "libudev-stub",
 ]