Fix mobile host list behind reverse proxies

[ZacharyZcR]

Summary

• try the mobile host list endpoint through the configured host, ssh, and root API bases
• reject unexpected non-host-list responses instead of treating them as an empty host list
• keep probing when an earlier candidate returns an empty list so reverse-proxy path mismatches can still resolve to the real host service

Fixes Termix-SSH/Support#876.

Tests

• git diff --check
• npx eslint app/main-axios.ts (0 errors, existing warnings remain)
• npx tsc --noEmit (fails on existing unrelated repo issues: missing expo-web-browser, WarpgateDialog toast callable type, TunnelManager optional endpointHost type)