feat(system): comprehensive branding, styling, and system feature update

- Relocate themes to assets/themes/ and update all references.
- Implement custom SDDM theme and Plymouth theme enhancements.
- Add themed templates for Alacritty, Hyprland, Waybar, and other apps.
- Introduce Makima key remapper module and configuration.
- Add Voxtype and Walker configurations.
- Implement systemd power management and timeout optimizations.
- Add Nautilus-python extensions for LocalSend.
- Update branding assets and ASCII art integration.

bin/appearance/nomarchy-theme-set

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+
+# Set the system theme declaratively.
+# Usage: nnomarchy-theme-set <theme-name>
+
+THEME_NAME="$1"
+
+if [[ -z $THEME_NAME ]]; then
+  echo "Usage: nnomarchy-theme-set <theme-name>"
+  exit 1
+fi
+
+STATE_DIR="$HOME/.config/home-manager"
+STATE_FILE="$STATE_DIR/state.json"
+
+# Resolve themes directory (Built-in from Nix store via Home Manager, or user extra)
+if [ -d "$HOME/.config/nnomarchy/themes/$THEME_NAME" ]; then
+  THEMES_DIR="$HOME/.config/nnomarchy/themes"
+else
+  THEMES_DIR="$HOME/.local/share/nnomarchy/themes"
+fi
+
+mkdir -p "$STATE_DIR"
+[[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"
+
+if [ ! -d "$THEMES_DIR/$THEME_NAME" ] && ! [[ "$THEME_NAME" == "nord" ]]; then
+  echo "Theme '$THEME_NAME' not found in $THEMES_DIR"
+  # Check if it exists in the palettes file
+  # (Assuming nnomarchy-palettes.nix is imported in Nix)
+fi
+
+TMP_JSON=$(mktemp)
+jq ".theme = \"$THEME_NAME\"" "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"
+
+# Sync to system state if we have permissions (for system-level theming like browser policies)
+SYSTEM_STATE_FILE="/etc/nixos/state.json"
+if [ -w "$SYSTEM_STATE_FILE" ] || [ -w "/etc/nixos" ]; then
+    sudo jq ".theme = \"$THEME_NAME\"" "$SYSTEM_STATE_FILE" > /tmp/system-state.json 2>/dev/null && sudo mv /tmp/system-state.json "$SYSTEM_STATE_FILE" 2>/dev/null || true
+fi
+
+# Try to find a background for this theme
+BG_DIR="$THEMES_DIR/$THEME_NAME/backgrounds"
+if [ -d "$BG_DIR" ]; then
+  BG=$(ls "$BG_DIR" | head -n 1)
+  if [ -n "$BG" ]; then
+    TMP_JSON=$(mktemp)
+    jq ".wallpaper = \"$BG_DIR/$BG\"" "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"
+  fi
+fi
+
+echo "Theme set to $THEME_NAME. Applying changes with env-update..."
+rm -rf "$HOME/.config/nnomarchy/current/theme"
+env-update
+
+nnomarchy-theme-set-templates
+
+nnomarchy-hook theme-set "$THEME_NAME"