feat(audio): add skip_sink_switch option for JACK/DAW routing (#263)

When enabled, skips pactl set-default-sink on stream creation.
Preserves external audio routing (JACK, qjackctl, Reaper).
Mutually exclusive with DAC passthrough.

cc

crates/qbz-audio/src/backend.rs

@@ -128,6 +128,10 @@ pub struct BackendConfig {
 
     /// When true, force PipeWire clock.force-quantum for bit-perfect playback
     pub pw_force_bitperfect: bool,
+
+    /// When true, skip `pactl set-default-sink` on stream creation.
+    /// Preserves external routing (JACK, qjackctl, Reaper).
+    pub skip_sink_switch: bool,
 }
 
 /// Result type for backend operations

crates/qbz-audio/src/pipewire_backend.rs

@@ -308,7 +308,10 @@ impl AudioBackend for PipeWireBackend {
         // Temporarily set default sink to target (if specified)
         // We DON'T restore it - let the user's system keep the selected device as default
         // This is actually the expected behavior: when you select a device, it becomes the default
-        if let Some(sink_name) = &target_sink {
+        // When skip_sink_switch is true, skip this entirely to preserve external routing (JACK/qjackctl)
+        if config.skip_sink_switch {
+            log::info!("[PipeWire Backend] Skipping set-default-sink (skip_sink_switch enabled)");
+        } else if let Some(sink_name) = &target_sink {
             log::info!("[PipeWire Backend] Setting default sink to: {}", sink_name);
 
             let set_result = Command::new("pactl")

crates/qbz-audio/src/settings.rs

@@ -50,6 +50,9 @@ pub struct AudioSettings {
     /// When true, force PipeWire clock.force-quantum alongside clock.force-rate for bit-perfect.
     /// Reset both to 0 on stop. PipeWire-only, requires dac_passthrough.
     pub pw_force_bitperfect: bool,
+    /// When true, skip `pactl set-default-sink` on stream creation.
+    /// Preserves external routing (JACK, qjackctl, Reaper).
+    pub skip_sink_switch: bool,
 }
 
 impl Default for AudioSettings {
@@ -72,6 +75,7 @@ impl Default for AudioSettings {
             normalization_target_lufs: -14.0, // Spotify/YouTube standard
             gapless_enabled: false, // Off by default — user opts in
             pw_force_bitperfect: false, // Off by default — experimental PipeWire feature
+            skip_sink_switch: false, // Off by default — only for JACK/DAW routing setups
         }
     }
 }
@@ -160,6 +164,10 @@ impl AudioSettingsStore {
             "ALTER TABLE audio_settings ADD COLUMN pw_force_bitperfect INTEGER DEFAULT 0",
             [],
         );
+        let _ = conn.execute(
+            "ALTER TABLE audio_settings ADD COLUMN skip_sink_switch INTEGER DEFAULT 0",
+            [],
+        );
 
         Ok(Self { conn })
     }
@@ -178,7 +186,7 @@ impl AudioSettingsStore {
     pub fn get_settings(&self) -> Result<AudioSettings, String> {
         self.conn
             .query_row(
-                "SELECT output_device, exclusive_mode, dac_passthrough, preferred_sample_rate, backend_type, alsa_plugin, alsa_hardware_volume, stream_first_track, stream_buffer_seconds, streaming_only, limit_quality_to_device, device_max_sample_rate, normalization_enabled, normalization_target_lufs, gapless_enabled, device_sample_rate_limits, pw_force_bitperfect FROM audio_settings WHERE id = 1",
+                "SELECT output_device, exclusive_mode, dac_passthrough, preferred_sample_rate, backend_type, alsa_plugin, alsa_hardware_volume, stream_first_track, stream_buffer_seconds, streaming_only, limit_quality_to_device, device_max_sample_rate, normalization_enabled, normalization_target_lufs, gapless_enabled, device_sample_rate_limits, pw_force_bitperfect, skip_sink_switch FROM audio_settings WHERE id = 1",
                 [],
                 |row| {
                     // Parse backend_type from JSON string
@@ -215,6 +223,7 @@ impl AudioSettingsStore {
                         normalization_target_lufs: row.get::<_, Option<f64>>(13)?.unwrap_or(-14.0) as f32,
                         gapless_enabled: row.get::<_, Option<i64>>(14)?.unwrap_or(0) != 0,
                         pw_force_bitperfect: row.get::<_, Option<i64>>(16)?.unwrap_or(0) != 0,
+                        skip_sink_switch: row.get::<_, Option<i64>>(17)?.unwrap_or(0) != 0,
                     })
                 },
             )

crates/qbz-player/src/player/mod.rs

@@ -508,6 +508,7 @@ fn try_init_stream_with_backend(
         exclusive_mode: audio_settings.exclusive_mode,
         alsa_plugin: audio_settings.alsa_plugin,
         pw_force_bitperfect: audio_settings.pw_force_bitperfect,
+        skip_sink_switch: audio_settings.skip_sink_switch,
     };
 
     // For ALSA backend with hw: devices, try direct ALSA first (Linux only)