[Bug] Rule-set proxy fails to fetch remote rule sets

[FSSocrates]

Description

The configured rule-set-proxy does not appear to work reliably for downloading remote rule sets.

I tested both the default configuration and gh-proxy, but the rule-set initialization still fails.

This seems to be independent of the Android VPN/TUN mode, since changing rule-set-proxy does not change whether SingCast starts the VPN.

Relevant code

rule-set-proxy is passed separately when the core configuration is started:

await LibCore.instance.startCoreWithContent(
  merged,
  ruleSetProxy: ruleSetProxy.value,
  enabledVpn: coreConfig.value.tunEnabled,
);

The application also persists it in settings.json and reads it independently from cache-tun.json.

Expected behavior

If a valid rule-set-proxy is configured, SingCast should use it to retrieve remote rule-set resources successfully.

If the proxy is unavailable, the error should clearly indicate that the rule-set download failed through the configured proxy.

Actual behavior

Rule-set initialization fails even when using a configured proxy such as gh-proxy.

Changing the rule-set proxy also does not affect the Android VPN/TUN behavior.

Important distinction

This appears to be a rule-set fetching/proxy issue, rather than a VPN/TUN issue.

The two mechanisms seem to be independent:

• rule-set-proxy → proxy for retrieving rule-set resources
• tunIf / tunEnabled / enabledVpn → Android VPN/TUN operation

Environment

• Android
• SingCast
• Rule-set proxy: default and gh-proxy both tested

Could you please check whether rule-set-proxy is being correctly applied when the core initializes and downloads remote rule sets?