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/tests/fixtures/video_frame_meta.json

@@ -0,0 +1,32 @@
+[
+	{
+		"bridgeVersion": 14,
+		"participantSid": "PA_remoteB12345",
+		"trackSid": "TR_remoteVideo01",
+		"trackName": "screen",
+		"source": "screen_share",
+		"width": 1920,
+		"height": 1080,
+		"timestampUs": 123456789
+	},
+	{
+		"bridgeVersion": 14,
+		"participantSid": "PA_77jesWWtSMge",
+		"trackSid": "TR_VShJ9y2A49ai6i",
+		"trackName": "camera",
+		"source": "camera",
+		"width": 1280,
+		"height": 720,
+		"timestampUs": 0
+	},
+	{
+		"bridgeVersion": 14,
+		"participantSid": "PA_remoteB12345",
+		"trackSid": "TR_remoteVideo02",
+		"trackName": "screen",
+		"source": "screen_share",
+		"width": 640,
+		"height": 360,
+		"timestampUs": 4294967296
+	}
+]