feat(gui): branded app icon in the sidebar header and login

The sidebar header and the login page used the generic folder-remote-symbolic
icon. Ship the app icon from packaging/ in the GUI resources and use it in
both places, so the in-app brand matches the launcher even when the app runs
uninstalled.

crates/pdfs-gui/build.rs

@@ -26,4 +26,5 @@ fn main() {
     println!("cargo:rerun-if-changed=resources/pdfs.gresource.xml");
     println!("cargo:rerun-if-changed=resources/icons");
     println!("cargo:rerun-if-changed=resources/style.css");
+    println!("cargo:rerun-if-changed=../../packaging/io.narl.proton-drive-linux.svg");
 }

crates/pdfs-gui/resources/pdfs.gresource.xml

@@ -9,6 +9,9 @@
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-upload-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-offline-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-online-only-symbolic.svg</file>
+    <!-- The app icon, from the one file packaging installs, so the in-app brand
+         matches the launcher and resolves even when nothing is installed. -->
+    <file alias="scalable/apps/io.narl.proton-drive-linux.svg" preprocess="xml-stripblanks">../../../packaging/io.narl.proton-drive-linux.svg</file>
   </gresource>
   <!-- The app stylesheet, loaded once at startup. Colours come from the
        libadwaita palette so the app follows the system accent, light/dark and

crates/pdfs-gui/resources/style.css

@@ -9,7 +9,6 @@
 
 /* Brand */
 .brand-title { font-size: 1.6rem; font-weight: 800; }
-.brand-icon { color: #6d4aff; }
 
 /* Sidebar footer */
 .sidebar-footer { padding: 6px 12px 12px 12px; }

crates/pdfs-gui/src/app/main.rs

@@ -884,8 +884,8 @@ fn build_sidebar(footer: &gtk4::Box) -> (adw::NavigationPage, gtk4::ListBox) {
     });
 
     let brand = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
-    let icon = gtk4::Image::from_icon_name("folder-remote-symbolic");
-    icon.add_css_class("brand-icon");
+    let icon = gtk4::Image::from_icon_name(APP_ID);
+    icon.set_pixel_size(24);
     brand.append(&icon);
     let name = gtk4::Label::new(Some("Proton Drive"));
     name.add_css_class("heading");

crates/pdfs-gui/src/app/pages/login.rs

@@ -52,9 +52,8 @@ pub(crate) fn build_login_page() -> (gtk4::Widget, LoginState) {
     login_status.add_css_class("dim-label");
 
     let header = gtk4::Box::new(gtk4::Orientation::Vertical, 4);
-    let logo = gtk4::Image::from_icon_name("folder-remote-symbolic");
-    logo.set_pixel_size(64);
-    logo.add_css_class("brand-icon");
+    let logo = gtk4::Image::from_icon_name(APP_ID);
+    logo.set_pixel_size(96);
     let title = gtk4::Label::new(Some("Proton Drive"));
     title.add_css_class("brand-title");
     header.append(&logo);