Play Framework

fix(crypto): add legacy password-hash verify helper for 1.12->1.13 migration (PF-132)

This fork's passwordHash(input) silently switched from Base64 MD5 to salted
PBKDF2, so apps that authenticated via passwordHash(input).equals(stored)
reject every pre-upgrade credential after upgrade with no way to verify the
old hash. Add @Deprecated checkPasswordLegacy(input, storedHash): recomputes
the legacy Base64 digest for MD5/SHA-1/SHA-256/SHA-512 and constant-time
compares (MessageDigest.isEqual, no short-circuit across algorithms).
Javadoc documents the re-hash-on-login migration pattern. Existing
passwordHash/passwordHashPBKDF2/checkPasswordPBKDF2 behavior unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
(cherry picked from commit a501371064c8240464d478c8965ad2a121e3fa00)