refactor: major architectural restructure for theme-centric organization

Theme System:
- Move all theme app configs to apps/ subdirectory (20 themes)
- Add theme-loader.nix for dynamic theme config deployment
- Simplify stylix.nix to focus on base theming only

Override System:
- Add overrides.nix for file-based config overrides
- Add behavior-configs.nix for non-visual configuration
- Split hypr/nomarchy.conf into behavior vs visual sections

Module Improvements:
- Add lib.mkDefault to all customizable settings
- Add modules/lib/ with shared utilities and state schema
- Update all home and system modules for downstream overridability

Installer:
- New minimal TTY installer (installer/install.sh)
- Golden path: BTRFS + LUKS2 (disko-golden.nix)
- New installer-iso.nix for TTY-only installation
- Keep graphical installer as installerIsoGraphical option

Cleanup:
- Remove obsolete install.sh, disko-ext4.nix, install-nomarchy.sh
- Update live-iso.nix references
- Add .claude/ to .gitignore for local IDE settings

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

bin/appearance/nomarchy-theme-bg-next

@@ -3,7 +3,7 @@
 # Cycles through the background images available for the current theme.
 # Declarative + Hybrid (instant swww) for Nomarchy NixOS.
 
-STATE_DIR="$HOME/.config/home-manager"
+STATE_DIR="$HOME/.config/nomarchy"
 STATE_FILE="$STATE_DIR/state.json"
 mkdir -p "$STATE_DIR"
 [[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"
@@ -45,7 +45,7 @@ NEXT_INDEX=$(((INDEX + 1) % TOTAL))
 NEW_BG="$BG_DIR/${BACKGROUNDS[$NEXT_INDEX]}"
 
 TMP_JSON=$(mktemp)
-jq ".wallpaper = \"$NEW_BG\"" "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"
+jq --arg wp "$NEW_BG" '.wallpaper = $wp' "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"
 
 # Instant feedback via swww
 if pgrep -x swww-daemon >/dev/null; then