Implement Driftwood AppImage manager

data/app.driftwood.Driftwood.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Name=Driftwood
+Comment=Modern AppImage manager for GNOME desktops
+Exec=driftwood
+Icon=app.driftwood.Driftwood
+Terminal=false
+Type=Application
+Categories=System;PackageManager;GTK;
+Keywords=AppImage;Application;Manager;Package;
+StartupNotify=true

data/app.driftwood.Driftwood.gschema.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<schemalist gettext-domain="driftwood">
+  <schema id="app.driftwood.Driftwood" path="/app/driftwood/Driftwood/">
+    <key name="window-width" type="i">
+      <default>900</default>
+      <summary>Window width</summary>
+      <description>The width of the main application window.</description>
+    </key>
+    <key name="window-height" type="i">
+      <default>600</default>
+      <summary>Window height</summary>
+      <description>The height of the main application window.</description>
+    </key>
+    <key name="window-maximized" type="b">
+      <default>false</default>
+      <summary>Window maximized</summary>
+      <description>Whether the main application window is maximized.</description>
+    </key>
+    <key name="scan-directories" type="as">
+      <default>['~/Applications', '~/Downloads']</default>
+      <summary>Scan directories</summary>
+      <description>Directories to scan for AppImage files.</description>
+    </key>
+    <key name="view-mode" type="s">
+      <default>'grid'</default>
+      <summary>Library view mode</summary>
+      <description>The library view mode: grid or list.</description>
+    </key>
+    <key name="color-scheme" type="s">
+      <default>'default'</default>
+      <summary>Color scheme</summary>
+      <description>Application color scheme: default (follow system), force-light, or force-dark.</description>
+    </key>
+  </schema>
+</schemalist>

data/resources.gresource.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+  <gresource prefix="/app/driftwood/Driftwood">
+    <file alias="style.css">resources/style.css</file>
+  </gresource>
+</gresources>

data/resources/style.css

@@ -0,0 +1,72 @@
+/* Status badges */
+.status-badge {
+    border-radius: 8px;
+    padding: 2px 8px;
+    font-size: 8pt;
+    font-weight: 600;
+}
+
+.status-badge.success {
+    background: @success_bg_color;
+    color: @success_fg_color;
+}
+
+.status-badge.warning {
+    background: @warning_bg_color;
+    color: @warning_fg_color;
+}
+
+.status-badge.error {
+    background: @error_bg_color;
+    color: @error_fg_color;
+}
+
+.status-badge.info {
+    background: @accent_bg_color;
+    color: @accent_fg_color;
+}
+
+.status-badge.neutral {
+    background: @card_shade_color;
+    color: @window_fg_color;
+}
+
+/* App cards in grid view */
+.app-card {
+    padding: 12px;
+    border-radius: 12px;
+    background: @card_bg_color;
+    transition: background 150ms ease;
+}
+
+.app-card:hover {
+    background: @headerbar_shade_color;
+}
+
+.app-card-name {
+    font-weight: 600;
+    font-size: 10pt;
+}
+
+.app-card-version {
+    font-size: 8pt;
+    opacity: 0.7;
+}
+
+/* Badge row in app cards */
+.badge-row {
+    margin-top: 4px;
+}
+
+/* Detail view headings */
+.heading {
+    font-weight: 700;
+    font-size: 11pt;
+    opacity: 0.8;
+}
+
+/* Monospace text for paths and hashes */
+.monospace {
+    font-family: monospace;
+    font-size: 9pt;
+}