feat(rio): add terminal config and theme template

Add Rio terminal configuration with Omarchy theme, fonts, bindings,
and a theming template for programmatic theme generation.

config/rio/config.toml

@@ -0,0 +1,23 @@
+# See the full configuration reference: https://rioterm.com/docs/config
+
+copy-on-select = true
+theme = "omarchy"
+hide-mouse-cursor-when-typing = true
+draw-bold-text-with-light-colors = false
+line-height = 1.1
+
+[fonts]
+size = 16
+family = "MonaspiceNeNerdFontMono"
+disable-warnings-not-found = false
+
+[editor]
+program = "nvim"
+args = []
+
+[bindings]
+keys = [
+  { key = "up", with = "super | shift", action = "ScrollToPrevPrompt" },
+  { key = "down", with = "super | shift", action = "ScrollToNextPrompt" },
+]
+