[Android] Self-hosted instance discovery fails with user-installed CA (CERTIFICATE_VERIFY_FAILED)

Reproduction steps

Install a private CA on Android; open the self-hosted discovery endpoint successfully in Brave; enter the same HTTPS hostname into Fluxer's Android instance switcher; press Connect; observe the failure.

Expected behaviour

Fluxer should securely recognise a CA explicitly trusted by the user, while maintaining certificate-chain and hostname verification.

Actual behaviour

Instance discovery fails before login. The app displays a generic connection error, while ADB confirms CERTIFICATE_VERIFY_FAILED.

Build information

2026.10.100-beta.8

Platform

Android, Self-hosting

Evidence

DioException [unknown]: null Error: HandshakeException: Handshake error in client (OS Error: CERTIFICATE_VERIFY_FAILED: self signed certificate in certificate chain(handshake.cc:320)) StackTrace: #0 DioMixin.fetch (package:dio/src/dio_mixin.dart:598) #1 InstanceDiscoveryService.connectToEndpoint (package:fluxer_app/core/instance/instance_discovery_service.dart:58) #2 ActiveInstance.connectToEndpoint (package:fluxer_app/core/providers/active_instance_provider.dart:43) #3 InstanceSelector.connectToUrl (package:fluxer_app/features/auth/providers/instance_selector_provider.dart:255)