新增 niri/dms/gtk/qt/cava/fcitx5 等配置并添加 .gitignore

- 纳入版本管理: niri/(含 dms/), DankMaterialShell/, environment.d/,
  cava/, gtk-3.0/, gtk-4.0/, qt5ct/, qt6ct/, fcitx5/
- 新增 .gitignore: 排除 *.bak/*.backup*、fcitx5/conf/cached_layouts、
  DankMaterialShell 运行时标志
- 同步已有的 kitty/nvim/.zshrc 修改

cava/themes/solarized_dark

@@ -0,0 +1,15 @@
+[color]
+background = '#001e26'
+foreground = '#708183'
+
+gradient = 1
+gradient_color_1 = '#268bd2'
+gradient_color_2 = '#6c71c4'
+gradient_color_3 = '#cb4b16'
+
+horizontal_gradient = 1
+horizontal_gradient_color_1 = '#586e75'
+horizontal_gradient_color_2 = '#b58900'
+horizontal_gradient_color_3 = '#839496'
+
+blend_direction = 'up'