getDnsRecords and getDomainExpirationDate had regressed to shell_exec
(dig/whois) when domain code was moved into functions/domain.php; the
RDAP helper stack was dropped entirely. Restores the dns_get_record +
RDAP + port-43-socket-whois implementation from d1e1609b under the
current function names. getSslCertificate was unaffected.
Replace md5(file_contents)+randomString(2) naming with randomString(32).
No longer reads the file into memory (removes file_get_contents), so
validation is O(1) regardless of size or upload count. Add is_uploaded_file()
and UPLOAD_ERR_OK checks, use pathinfo() for extension extraction, and
return false consistently on all failures (oversize previously returned a
truthy error string that callers treated as a valid filename).
Replace srand()/rand() with random_int() for cryptographically secure,
unbiased key generation. The previous implementation seeded rand() from
microtime(), making TOTP secrets predictable if the generation time
could be approximated. Also removes modulo bias and dead while(1)
wrapper.
Output format is unchanged: 32 chars from the base32 alphabet (A-Z,
2-7), so existing TOTP enrollments are unaffected.
