keys: read damage is never a key failure; legacy key API removed

Damaged AACS units are holed, blanked and counted on every path instead
of stopping with E7013; failed batch partners fall back to side reads
and a wrong FMTS key is judged per key. ResolvedKeySet is the only AACS
decrypt door; a raw whole-disc reader never decrypts and refuses titles
with no stream folder (E6003) or a piece no held key opens (E7032).

tests/pass_n_patch_fix.rs

@@ -88,12 +88,6 @@ fn decrypt_keys_is_encrypted_variants() {
     let none = DecryptKeys::None;
     assert!(!none.is_encrypted());
 
-    let aacs = DecryptKeys::Aacs {
-        unit_keys: vec![],
-        format: libfreemkv::disc::ContentFormat::BdTs,
-    };
-    assert!(aacs.is_encrypted());
-
     let css = DecryptKeys::Css {
         title_key: [0u8; 5],
     };