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>

themes/m3ui-dark/theme.conf

@@ -0,0 +1,117 @@
+[Metadata]
+Name=Material 3 Dark (m3ui)
+Version=1
+Author=m3ui
+Description=Material 3 theme for the m3ui Fcitx5 user interface
+ScaleWithDPI=True
+
+[InputPanel]
+SurfaceColor=#2F282AF5
+OutlineColor=#FFFFFF1F
+HighlightFillColor=#5E3A49FF
+PanelRadius=18
+ItemRadius=12
+NormalColor=#EBE0E1
+HighlightCandidateColor=#FFD9E2
+HighlightColor=#FFB0C9
+HighlightBackgroundColor=#5E3A49
+CandidateLabelColor=#A8969B
+HighlightCandidateLabelColor=#E6BDC9
+CandidateCommentColor=#D5C2C6
+HighlightCandidateCommentColor=#FFD9E2
+LabelTextSizeFactor=78
+CommentTextSizeFactor=78
+FullWidthHighlight=False
+PageButtonAlignment=Center
+
+[InputPanel/ContentMargin]
+Left=3
+Right=3
+Top=3
+Bottom=3
+
+[InputPanel/TextMargin]
+Left=8
+Right=8
+Top=5
+Bottom=5
+
+[InputPanel/Background]
+Image=panel.svg
+
+[InputPanel/Background/Margin]
+Left=12
+Right=12
+Top=12
+Bottom=12
+
+[InputPanel/Highlight]
+Image=highlight.svg
+
+[InputPanel/Highlight/Margin]
+Left=10
+Right=10
+Top=10
+Bottom=10
+
+[InputPanel/PrevPage]
+Image=prev.svg
+
+[InputPanel/PrevPage/ClickMargin]
+Left=4
+Right=4
+Top=4
+Bottom=4
+
+[InputPanel/NextPage]
+Image=next.svg
+
+[InputPanel/NextPage/ClickMargin]
+Left=4
+Right=4
+Top=4
+Bottom=4
+
+[Menu]
+NormalColor=#EBE0E1
+HighlightCandidateColor=#FFD9E2
+Spacing=2
+
+[Menu/Background]
+Image=panel.svg
+
+[Menu/Background/Margin]
+Left=12
+Right=12
+Top=12
+Bottom=12
+
+[Menu/ContentMargin]
+Left=4
+Right=4
+Top=4
+Bottom=4
+
+[Menu/Highlight]
+Image=highlight.svg
+
+[Menu/Highlight/Margin]
+Left=10
+Right=10
+Top=10
+Bottom=10
+
+[Menu/Separator]
+Color=#514347
+
+[Menu/CheckBox]
+Image=radio.svg
+
+[Menu/SubMenu]
+Image=arrow.svg
+
+[Menu/TextMargin]
+Left=8
+Right=8
+Top=5
+Bottom=5