The composer classmap autoloader loads the real PRAutoBlogger_Encryption
before our eval() stub runs, so class_exists() is always true and the stub
is never installed. Two consequences:
1. Provider tests set 'enc:fake-key' and the real decrypt() path ran,
calling wp_salt() which isn't stubbed. Switched to plaintext keys
so is_encrypted() short-circuits and no crypto runs.
2. Support test for the decrypt path now uses a real encrypt/decrypt
round-trip with a stubbed wp_salt() returning a deterministic
32-char salt. This exercises the actual code path users hit in
production, not a lying stub.
Removes the dead eval() stubs that were being skipped anyway.
8bedecd2dd