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/webauthn/vm_tests/set_pin.py

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import ctypes
+import sys
+
+device_path = sys.argv[1].encode() if len(sys.argv) > 1 else b"/dev/hidraw4"
+pin = sys.argv[2].encode() if len(sys.argv) > 2 else b"123456"
+
+lib = ctypes.CDLL("libfido2.so.1")
+lib.fido_init(0)
+lib.fido_dev_new.restype = ctypes.c_void_p
+lib.fido_strerr.restype = ctypes.c_char_p
+
+dev = lib.fido_dev_new()
+rc = lib.fido_dev_open(ctypes.c_void_p(dev), device_path)
+if rc != 0:
+    print(f"open failed rc={rc} {lib.fido_strerr(rc).decode()}")
+    sys.exit(1)
+rc = lib.fido_dev_set_pin(ctypes.c_void_p(dev), pin, None)
+print(f"set_pin rc={rc} {lib.fido_strerr(rc).decode()}")
+lib.fido_dev_close(ctypes.c_void_p(dev))
+sys.exit(0 if rc == 0 else 1)