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/webrtc-sender/vendor/webrtc-sys/Cargo.toml.orig

@@ -0,0 +1,28 @@
+[package]
+name = "webrtc-sys"
+version = "0.3.33"
+edition.workspace = true
+homepage = "https://livekit.io"
+license.workspace = true
+description = "Unsafe bindings to libwebrtc"
+repository.workspace = true
+
+[features]
+default = []
+
+[dependencies]
+cxx = "1.0"
+log = { workspace = true }
+
+[build-dependencies]
+webrtc-sys-build = { workspace = true }
+cxx-build = "1.0"
+glob = "0.3"
+cc = "1.0"
+pkg-config = "0.3.22"
+
+[target.'cfg(target_os = "linux")'.build-dependencies]
+pkg-config = "0.3.22"
+
+[dev-dependencies]
+env_logger = { workspace = true }