Add native self-hosted instance connection to fluxer_desktop

Trimmed monorepo checkout (fluxer_desktop + packages/voice_engine_v2 +
tools/ci) with a "Connect to a Different Server" menu item and popout
that lets the desktop app switch to any self-hosted Fluxer instance,
plus fixes for well-known discovery on single-domain self-hosted
deployments and a false-positive ERR_ABORTED on same-origin client
redirects during the switch. Defaults to chat.fluxr.chat and uses an
isolated userData directory from the official build.

fluxer_desktop/native/linux-audio-capture/benches/end_to_end.rs

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use std::hint::black_box;
+
+use criterion::{Criterion, criterion_group, criterion_main};
+use fluxer_audio_mix::{AUDIO_OUTPUT_FRAMES, SourceRing, SourceRingProducer};
+use fluxer_linux_audio_capture::audio_mix_runtime_bench_helpers::{
+    AudioMixRuntimeBuilder, CaptureSource, MIX_CHANNELS, MIX_SAMPLE_RATE_HZ, MIX_TICK_PERIOD_NS,
+    NullMixOutputSink,
+};
+
+const BENCH_SOURCE_COUNT: usize = 8;
+
+fn build_sources_and_runtime() -> (
+    Vec<CaptureSource>,
+    fluxer_linux_audio_capture::audio_mix_runtime_bench_helpers::AudioMixRuntime,
+) {
+    let mut sources = Vec::with_capacity(BENCH_SOURCE_COUNT);
+    let mut builder = AudioMixRuntimeBuilder::new();
+    for n in 0..BENCH_SOURCE_COUNT {
+        let (source, consumer) =
+            CaptureSource::create(n as u64 + 1, MIX_SAMPLE_RATE_HZ, MIX_CHANNELS).expect("source");
+        sources.push(source);
+        builder = builder.add_source(n as u64 + 1, consumer);
+    }
+    let runtime = builder.build(NullMixOutputSink).expect("build");
+    (sources, runtime)
+}
+
+fn fill_sources(sources: &mut [CaptureSource], frames: usize) {
+    assert!(!sources.is_empty());
+    assert!(frames > 0);
+    let payload: Vec<i16> = (0..frames).map(|n| ((n as i16) % 4096) - 2048).collect();
+    for source in sources.iter_mut() {
+        let _pushed = source.ingest_skip_apm(&payload);
+    }
+}
+
+fn bench_end_to_end_tick(c: &mut Criterion) {
+    let mut group = c.benchmark_group("linux_audio_end_to_end");
+    group.sample_size(50);
+    group.bench_function("8_sources_capture_ring_mix_policy", |b| {
+        let (mut sources, mut runtime) = build_sources_and_runtime();
+        let mut tick_index: u64 = 0;
+        b.iter(|| {
+            fill_sources(&mut sources, AUDIO_OUTPUT_FRAMES);
+            let frame = runtime
+                .run_one_tick_blocking(tick_index * MIX_TICK_PERIOD_NS)
+                .expect("frame");
+            tick_index = tick_index.wrapping_add(1);
+            black_box(frame);
+        });
+    });
+    group.finish();
+}
+
+#[allow(dead_code)]
+fn _producer_helper(producer: SourceRingProducer) -> SourceRingProducer {
+    producer
+}
+
+#[allow(dead_code)]
+fn _ring_helper() -> usize {
+    let _: usize = SourceRing::create(8192, 48_000).map(|_| 0).unwrap_or(0);
+    0
+}
+
+criterion_group!(benches, bench_end_to_end_tick);
+criterion_main!(benches);