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/system-hunspell/package.json

@@ -0,0 +1,27 @@
+{
+	"name": "@fluxer/system-hunspell",
+	"version": "0.0.0",
+	"description": "",
+	"private": true,
+	"license": "AGPL-3.0-or-later",
+	"os": [
+		"linux"
+	],
+	"cpu": [
+		"x64",
+		"arm64"
+	],
+	"main": "index.js",
+	"types": "index.d.ts",
+	"files": [
+		"index.js",
+		"index.d.ts",
+		"loader-diagnostics.cjs",
+		"system-hunspell.linux-x64-gnu.node",
+		"system-hunspell.linux-arm64-gnu.node"
+	],
+	"scripts": {
+		"build": "cargo run --locked --quiet --manifest-path ../../../tools/ci/Cargo.toml -- build-desktop-native-addon",
+		"test": "cargo test --manifest-path Cargo.toml"
+	}
+}