tests: read_aacs_inputs Long-AD coverage; scrub title names from comments

Add a precommit fixture proving Disc::read_aacs_inputs reads a Long-AD,
multi-extent /AACS/Unit_Key_RO.inf in full — the exact input the online
key-request path depends on (no disc/deploy needed). Make
read_aacs_inputs_from_reader pub(crate) for the test.

Reword internal comments/doc examples to generic descriptions instead of
specific media titles.

src/disc/mod.rs

@@ -1299,7 +1299,7 @@ impl Disc {
     /// zero-padded, so reading either ships up to ~124 MiB of nothing —
     /// trim to the record stream so callers send/store a few MB, not
     /// 128 MiB.
-    fn read_aacs_inputs_from_reader(
+    pub(crate) fn read_aacs_inputs_from_reader(
         reader: &mut dyn SectorSource,
         udf_fs: &udf::UdfFs,
     ) -> Result<(Vec<u8>, Vec<u8>)> {