fix(api): resolve mobile host endpoint behind proxies

[ZacharyZcR]

Summary

• probe supported host API bases when a reverse proxy does not expose the canonical /host prefix
• accept only valid host-list response shapes and preserve legitimate empty lists
• reuse the resolved API base for subsequent host operations
• stop fallback on authentication failures and bypass stale proxy caches for host-list reads

Verification

• npm run format:check
• npm run lint (0 errors; existing warnings only)
• npm run verify:android-network-security
• npx tsc --noEmit
• git diff --check

Fixes Termix-SSH/Support#876.