Context

From PR #328 review:

The HTTP fallback in SiteCapabilitiesDiscovery doesn't work because the server isn't actually speaking HTTPS. When this happens, the user doesn't get a clear error message explaining the problem.

Expected Behavior

When connecting to a site that doesn't support HTTPS, the app should display a clear, user-friendly error message explaining that the site doesn't support a secure connection.

Current Behavior

The connection silently fails or falls through to default capabilities without informing the user about the HTTPS issue.

Relevant Code

• android/app/src/main/java/com/example/gutenbergkit/SiteCapabilitiesDiscovery.kt — discoverCapabilitiesViaHttp method (GutenbergKit PR #328)