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>

assets/themes/lumon/apps/swayosd.css

@@ -0,0 +1,44 @@
+@define-color background-color #1b2d40;
+@define-color border-color #304860;
+@define-color label #d6e2ee;
+@define-color image #d6e2ee;
+@define-color progress #6fb8e3;
+@define-color edge-light #f2fcff;
+
+/* Cancel out Nomarchy defaults */
+window:not(:backdrop),
+window:backdrop {
+    border: none;
+    border-width: 0;
+    background-color: transparent;
+    box-shadow: none;
+    padding: 12px;
+}
+
+/* Draw the Lumon OSD shell */
+window:not(:backdrop) #container,
+window:backdrop #container {
+    border: 2px solid alpha(@border-color, 0.92);
+    background-color: alpha(@background-color, 0.95);
+    padding: 12px 16px;
+    background-clip: padding-box;
+}
+
+image,
+label {
+    color: @label;
+}
+
+progressbar {
+    min-height: 8px;
+}
+
+progressbar trough {
+    background: alpha(@border-color, 0.24);
+    box-shadow: inset 0 1px rgba(242, 252, 255, 0.03);
+}
+
+progressbar progress {
+    background: linear-gradient(90deg, @progress, @edge-light);
+    box-shadow: 0 0 10px rgba(111, 184, 227, 0.18);
+}