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/mac-app-audio/index.d.ts

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {EventEmitter} from 'node:events';
+
+export interface MacAppAudioBackendInfo {
+	backend: string;
+	supported: boolean;
+	reason: string;
+	minMacosVersion: string;
+	minMacosVersionCoreaudio: string;
+	detectedMacosVersion?: string;
+	sckAvailable: boolean;
+	coreaudioAvailable: boolean;
+}
+
+export declare function getBackendInfo(): MacAppAudioBackendInfo;
+
+export interface MacBackendAvailability {
+	sck?: {
+		supported: boolean;
+		macosVersion?: string;
+	};
+	coreaudio?: {
+		supported: boolean;
+	};
+	screenPermission?: string;
+	audioPermission?: string;
+}
+
+export interface MacApplicationDescriptor {
+	pid: number;
+	bundleId?: string;
+	name: string;
+}
+
+export interface ProcessLoopbackOptions {
+	excludeSelf?: boolean;
+	includeProcessTree?: boolean;
+	backend?: 'sck' | 'coreaudio' | 'auto';
+	macBackend?: 'sck' | 'coreaudio' | 'auto';
+	captureScope?: 'process' | 'system';
+	macCaptureScope?: 'process' | 'system';
+	scope?: 'process' | 'system';
+}
+
+export interface AudioFrame {
+	samples: Float32Array;
+	sampleRate: number;
+	channels: number;
+	timestampUs: number;
+}
+
+export declare const loadError: Error | null;
+
+export declare function __setBindingForTests(binding: unknown): void;
+
+export declare function pidFromWindowId(windowId: number): number;
+
+export declare function listAudibleApplications(): Promise<Array<MacApplicationDescriptor>>;
+
+export declare function getBackendAvailability(): Promise<MacBackendAvailability>;
+
+export declare interface ProcessLoopback {
+	on(event: 'frame', listener: (frame: AudioFrame) => void): this;
+	on(event: 'error', listener: (err: Error) => void): this;
+	on(event: 'closed', listener: () => void): this;
+	on(event: string | symbol, listener: (...args: Array<unknown>) => void): this;
+	off(event: 'frame', listener: (frame: AudioFrame) => void): this;
+	off(event: 'error', listener: (err: Error) => void): this;
+	off(event: 'closed', listener: () => void): this;
+	off(event: string | symbol, listener: (...args: Array<unknown>) => void): this;
+	emit(event: 'frame', frame: AudioFrame): boolean;
+	emit(event: 'error', err: Error): boolean;
+	emit(event: 'closed'): boolean;
+}
+
+export declare class ProcessLoopback extends EventEmitter {
+	constructor(pid: number, options?: ProcessLoopbackOptions);
+
+	start(): Promise<void>;
+
+	stop(): Promise<void>;
+}