Add Material 3 candidate window addon for Fcitx5

Fork of the classicui addon (Fcitx5 5.1.23) with a Material 3 look, spring
based animations and a right click action menu for candidates.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

config/m3ui.conf.example

@@ -0,0 +1,19 @@
+Vertical Candidate List=False
+WheelForPaging=True
+Font="Noto Sans CJK SC 11"
+MenuFont="Noto Sans CJK SC 10"
+TrayFont="Noto Sans CJK SC 10"
+Theme=m3ui-light
+DarkTheme=m3ui-dark
+UseDarkTheme=True
+UseAccentColor=False
+PerScreenDPI=True
+ForceWaylandDPI=0
+EnableFractionalScale=True
+Animations=True
+Bounce=True
+SpatialStiffness=2000
+SpatialDamping=62
+EffectsStiffness=3800
+SlideDistance=22
+SlideDirection=0