Add Pi theme based on system theme

Based entirely on the work of @robzolkos in #5711. That attempt was
adapted to better fit the standard templating system while also adding
color mixing for use in other themes.

bin/omarchy-theme-set

@@ -173,6 +173,7 @@ post_theme_commands=(
   omarchy-restart-helix
   omarchy-theme-set-foot
   omarchy-theme-set-gnome
+  omarchy-theme-set-pi
   omarchy-theme-set-browser
   omarchy-theme-set-vscode
   omarchy-theme-set-obsidian

bin/omarchy-theme-set-pi

@@ -0,0 +1,76 @@
+#!/bin/bash
+
+# omarchy:summary=Sync the generated Omarchy Pi theme
+# omarchy:args=[--activate]
+# omarchy:hidden=true
+
+set -euo pipefail
+
+CURRENT_THEME_PATH="$HOME/.config/omarchy/current/theme"
+PI_SOURCE_PATH="$CURRENT_THEME_PATH/pi.json"
+PI_AGENT_DIR="$HOME/.pi/agent"
+PI_THEME_DIR="$PI_AGENT_DIR/themes"
+PI_THEME_PATH="$PI_THEME_DIR/omarchy-system.json"
+PI_SETTINGS_PATH="$PI_AGENT_DIR/settings.json"
+PI_ACTIVATE=0
+
+usage() {
+  echo "Usage: omarchy-theme-set-pi [--activate]"
+}
+
+for arg in "$@"; do
+  case "$arg" in
+    --activate)
+      PI_ACTIVATE=1
+      ;;
+    -h | --help)
+      usage
+      exit 0
+      ;;
+    *)
+      usage >&2
+      exit 1
+      ;;
+  esac
+done
+
+if [[ ! -f $PI_SOURCE_PATH ]]; then
+  if (( PI_ACTIVATE == 1 )); then
+    echo "Pi theme source missing: $PI_SOURCE_PATH" >&2
+    echo "Run omarchy-theme-refresh after selecting an Omarchy theme." >&2
+    exit 1
+  fi
+
+  exit 0
+fi
+
+if (( PI_ACTIVATE == 0 )) && [[ ! -d $PI_AGENT_DIR ]]; then
+  exit 0
+fi
+
+write_setting_theme() {
+  local tmp
+
+  mkdir -p "$PI_AGENT_DIR"
+
+  if [[ -f $PI_SETTINGS_PATH ]]; then
+    tmp=$(mktemp "$PI_SETTINGS_PATH.XXXXXX")
+    jq '.theme = "omarchy-system"' "$PI_SETTINGS_PATH" >"$tmp"
+    mv "$tmp" "$PI_SETTINGS_PATH"
+  else
+    cat >"$PI_SETTINGS_PATH" <<EOF
+{
+  "theme": "omarchy-system"
+}
+EOF
+  fi
+}
+
+mkdir -p "$PI_THEME_DIR"
+tmp=$(mktemp "$PI_THEME_PATH.XXXXXX")
+cp "$PI_SOURCE_PATH" "$tmp"
+mv "$tmp" "$PI_THEME_PATH"
+
+if (( PI_ACTIVATE == 1 )); then
+  write_setting_theme
+fi