feat: responsive full-window settings layout

The Settings screen now follows the full window width/height instead of a
fixed 460x500 card. Device/privacy pickers and the noise-gate slider fill
the available width, and controls are laid out in 2 columns so a single
dropdown never stretches across the whole window:

- Input Device | Output Device
- Mic Sensitivity | Network Privacy (top-aligned)
- The 8 custom chime path fields remain a 2-column grid

Section spacing tightened so everything (incl. Back) fits on 1080p without
scrolling. The styled card now fills the page (max_width cap dropped).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/mod.rs

@@ -482,68 +482,78 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                     .on_input(move |val| AppMessage::CustomSoundPathChanged(sound, val))
                     .style(t_style)
                     .padding(8)
-            ].spacing(4).width(iced::Length::Fixed(320.0))
+            ].spacing(4).width(iced::Length::Fill)
         };
 
         let settings_content = scrollable(
             column![
                 text("Settings").size(24).color(color_blue),
-                vertical_space(20.0),
-                text("Device Settings").size(14).color(color_subtext),
                 vertical_space(10.0),
+                text("Device Settings").size(14).color(color_subtext),
+                vertical_space(6.0),
+                row![
                     column![
                         text("Input Device").size(12).color(Color::from_rgb8(180, 180, 180)),
                         pick_list(
                             &state.input_devices[..],
                             state.selected_input.as_ref(),
                             AppMessage::InputDeviceSelected,
-                    ).width(iced::Length::Fixed(320.0)),
+                        ).width(iced::Length::Fill),
-                ].spacing(4).width(iced::Length::Fixed(320.0)),
+                    ].spacing(4).width(iced::Length::Fill),
-                vertical_space(10.0),
                     column![
                         text("Output Device").size(12).color(Color::from_rgb8(180, 180, 180)),
                         pick_list(
                             &state.output_devices[..],
                             state.selected_output.as_ref(),
                             AppMessage::OutputDeviceSelected,
-                    ).width(iced::Length::Fixed(320.0)),
+                        ).width(iced::Length::Fill),
-                ].spacing(4).width(iced::Length::Fixed(320.0)),
+                    ].spacing(4).width(iced::Length::Fill),
-                vertical_space(20.0),
+                ].spacing(20).width(iced::Length::Fill),
+                vertical_space(12.0),
+                row![
                     column![
                         text(format!("Mic Sensitivity (Noise Gate): {:.1}%", state.config.noise_gate_threshold * 100.0)).size(14).color(color_subtext),
                         slider(0.0..=0.1, state.config.noise_gate_threshold, AppMessage::NoiseGateChanged).step(0.001)
-                ].spacing(10).width(iced::Length::Fixed(320.0)),
+                    ].spacing(8).width(iced::Length::Fill),
-                vertical_space(20.0),
                     column![
                         text("Network Privacy").size(14).color(color_subtext),
                         pick_list(
                             &NetworkMode::ALL[..],
                             Some(state.config.network_mode),
                             AppMessage::NetworkModeSelected,
-                    ).width(iced::Length::Fixed(320.0)),
+                        ).width(iced::Length::Fill),
                         text(network_mode_hint(state.config.network_mode)).size(11).color(color_subtext),
                         text("Takes effect on your next room join.").size(11).color(color_surface),
-                ].spacing(6).width(iced::Length::Fixed(320.0)),
+                    ].spacing(4).width(iced::Length::Fill),
-                vertical_space(20.0),
+                ].spacing(20).align_y(iced::alignment::Vertical::Top).width(iced::Length::Fill),
+                vertical_space(12.0),
                 column![
                     text("Notification Chimes").size(14).color(color_subtext),
                     checkbox(state.config.notifications_enabled)
                         .label("Enable sound notifications")
                         .on_toggle(AppMessage::ToggleNotifications),
-                ].spacing(10).width(iced::Length::Fixed(320.0)),
+                ].spacing(8).width(iced::Length::Fill),
-                vertical_space(20.0),
+                vertical_space(12.0),
                 text("Custom Chime Files (WAV Paths)").size(14).color(color_subtext),
                 
+                row![
                     path_field("Self Join", Sound::SelfJoin),
-                path_field("Self Leave", Sound::SelfLeave),
                     path_field("Peer Join", Sound::PeerJoin),
+                ].spacing(20).width(iced::Length::Fill),
+                row![
+                    path_field("Self Leave", Sound::SelfLeave),
                     path_field("Peer Leave", Sound::PeerLeave),
+                ].spacing(20).width(iced::Length::Fill),
+                row![
                     path_field("Reconnect Attempt", Sound::ReconnectAttempt),
                     path_field("Reconnected", Sound::Reconnected),
+                ].spacing(20).width(iced::Length::Fill),
+                row![
                     path_field("Mic Toggle", Sound::MicToggle),
                     path_field("Reconnect Failed", Sound::ReconnectFailed),
+                ].spacing(20).width(iced::Length::Fill),
 
-                vertical_space(30.0),
+                vertical_space(14.0),
                 button(
                     text("Back")
                         .size(16)
@@ -556,21 +566,20 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
             ]
             .align_x(iced::alignment::Horizontal::Center)
             .spacing(10)
+            .width(iced::Length::Fill)
         );
 
         let settings_box = container(settings_content)
             .style(c_style(color_mantle, color_surface, 12.0))
-            .padding(30)
+            .padding(24)
-            .width(460)
+            .width(iced::Length::Fill)
-            .height(500);
+            .height(iced::Length::Fill);
 
-        let content = column![settings_box].align_x(iced::alignment::Horizontal::Center);
+        return container(settings_box)
-
-        return container(content)
             .width(iced::Length::Fill)
             .height(iced::Length::Fill)
+            .padding(24)
             .center_x(iced::Length::Fill)
-            .center_y(iced::Length::Fill)
             .style(c_style(color_crust, Color::TRANSPARENT, 0.0))
             .into();
     }