KWin: switch libepoxy-stub→libepoxy (real 3D dispatch)

Replaced the libepoxy-stub (hardcoded inline stubs returning 0 for
all EGL/GLES extension queries) with the real libepoxy v6.0 2026
recipe. libepoxy builds against Mesa EGL/GLES2 with full function
pointer dispatch via epoxy_*_resolve().

The real recipe was already populated with full source (meson build,
dispatch_egl.c, dispatch_glx.c, etc.) but was never wired into KWin.
libudev-stub remains until libudev source is populated.

This unblocks KWin's cmake configure step which needs real
epoxy::epoxy cmake target with actual GL/EGL function pointer
resolution, not the hardcoded-zero stub.

local/recipes/kde/kwin/recipe.toml

@@ -1,11 +1,11 @@
 # KWin — real cmake build of the KDE Wayland compositor/window manager.
 # null+8 Wayland crash is verified FIXED in qtwaylandscanner (commits
 # de2d74c37e + 882c2974ec). Cross-build still bounded by:
-#   - libepoxy-stub / libudev-stub: policy debt; real libepoxy/libudev
-#     recipes exist but source is not yet populated. Stub packages stage
-#     the cmake targets KWin links against (epoxy::epoxy, UDev::UDev).
-#     When real libepoxy and libudev get populated source, switch KWin's
-#     deps to those recipes and remove the stubs.
+#   - libudev-stub: policy debt; real libudev recipe exists but source is
+#     not yet populated. Stub provides UDev::UDev cmake target KWin needs.
+#   - libepoxy: switched from stub to real libepoxy v6.0 2026 (2026-07-09).
+#     Provides epoxy::epoxy cmake target with real EGL/GLES function pointer
+#     dispatch, replacing the hardcoded-zero stub.
 #   - KF6Svg: KF6::Svg is not built on Redox. KWin's CMakeLists touches
 #     the target in optional paths; the recipe stubs it locally.
 #   - Sensors / UiTools: removed from CMakeLists.txt (these components
@@ -44,7 +44,7 @@ dependencies = [
     "kdecoration",
     "kf6-kcmutils",
     "plasma-wayland-protocols",
-    "libepoxy-stub",
+    "libepoxy",
     "libudev-stub",
     "wayland-protocols",
     "redbear-compositor",