Initial commit — ferrosonic terminal Subsonic client

Terminal-based Subsonic music client in Rust featuring bit-perfect audio
playback via PipeWire sample rate switching, gapless playback, MPRIS2
desktop integration, cava audio visualizer with theme-matched gradients,
13 built-in color themes with custom TOML theme support, mouse controls,
artist/album browser, playlist support, and play queue management.

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

src/ui/pages/settings.rs

@@ -0,0 +1,123 @@
+//! Settings page with app preferences and theming
+
+use ratatui::{
+    layout::{Constraint, Layout, Rect},
+    style::{Modifier, Style},
+    widgets::{Block, Borders, Paragraph},
+    Frame,
+};
+
+use crate::app::state::AppState;
+use crate::ui::theme::ThemeColors;
+
+/// Render the settings page
+pub fn render(frame: &mut Frame, area: Rect, state: &AppState) {
+    let colors = *state.settings_state.theme_colors();
+
+    let block = Block::default()
+        .borders(Borders::ALL)
+        .title(" Settings ")
+        .border_style(Style::default().fg(colors.border_focused));
+
+    let inner = block.inner(area);
+    frame.render_widget(block, area);
+
+    if inner.height < 8 {
+        return;
+    }
+
+    let settings = &state.settings_state;
+
+    // Layout fields vertically with spacing
+    let chunks = Layout::vertical([
+        Constraint::Length(1), // Spacing
+        Constraint::Length(2), // Theme selector
+        Constraint::Length(1), // Spacing
+        Constraint::Length(2), // Cava toggle
+        Constraint::Min(1),    // Remaining space
+    ])
+    .split(inner);
+
+    // Theme selector (field 0)
+    render_option(
+        frame,
+        chunks[1],
+        "Theme",
+        settings.theme_name(),
+        settings.selected_field == 0,
+        &colors,
+    );
+
+    // Cava toggle (field 1)
+    let cava_value = if !state.cava_available {
+        "Off (cava not found)"
+    } else if settings.cava_enabled {
+        "On"
+    } else {
+        "Off"
+    };
+
+    render_option(
+        frame,
+        chunks[3],
+        "Cava Visualizer",
+        cava_value,
+        settings.selected_field == 1,
+        &colors,
+    );
+
+    // Help text at bottom
+    let help_text = match settings.selected_field {
+        0 => "← → or Enter to change theme (auto-saves)",
+        1 if state.cava_available => "← → or Enter to toggle cava visualizer (auto-saves)",
+        1 => "cava is not installed on this system",
+        _ => "",
+    };
+    let help = Paragraph::new(help_text).style(Style::default().fg(colors.muted));
+
+    let help_area = Rect::new(
+        inner.x,
+        inner.y + inner.height.saturating_sub(2),
+        inner.width,
+        1,
+    );
+    frame.render_widget(help, help_area);
+}
+
+/// Render an option selector
+fn render_option(
+    frame: &mut Frame,
+    area: Rect,
+    label: &str,
+    value: &str,
+    selected: bool,
+    colors: &ThemeColors,
+) {
+    let label_style = if selected {
+        Style::default()
+            .fg(colors.primary)
+            .add_modifier(Modifier::BOLD)
+    } else {
+        Style::default().fg(colors.highlight_fg)
+    };
+
+    let value_style = if selected {
+        Style::default().fg(colors.accent)
+    } else {
+        Style::default().fg(colors.muted)
+    };
+
+    // Label
+    let label_text = Paragraph::new(label).style(label_style);
+    frame.render_widget(label_text, Rect::new(area.x, area.y, area.width, 1));
+
+    // Value with arrows
+    let value_text = if selected {
+        format!("  ◀ {} ▶", value)
+    } else {
+        format!("    {}", value)
+    };
+
+    let value_para = Paragraph::new(value_text).style(value_style);
+    frame.render_widget(value_para, Rect::new(area.x, area.y + 1, area.width, 1));
+}