Stop naming specific commercial discs in comments and tests

Fifteen references across six files named the discs a defect was first
seen on. The parser leak found earlier was not an isolated slip — the
same habit runs through the mux comments, the changelog and the AACS
content verdict, where a title name was standing in for the shape of
the problem.

Every one is replaced with the property that actually mattered: a
multi-clip title, a UHD Dolby Vision profile 7 dual-layer stream, a
disc carrying an authored-bad TS packet. The comments are more useful
for it — the reader needs to recognise the shape on a disc they have,
not the one we happened to have.

`SEG_MainFeature` stays: the parser matches on that literal, so it is
a format token rather than a title.

CHANGELOG.md

@@ -1119,7 +1119,7 @@ consumers are the in-tree toolchain crates.
   The direct-to-MKV path now gives the drive its full ECC recovery budget on a
   bad sector (matching the multipass rip) instead of reporting a read failure a
   multipass rip would have recovered.
-- **4K decode glitches at non-seamless clip joins fixed (Top Gun class).**
+- **4K decode glitches at non-seamless clip joins fixed.**
   Titles assembled from clips joined at non-seamless boundaries no longer drop
   reference frames at the join ("Could not find ref" stutter); the splice
   keyframe is rewritten so the decoder discards only the genuinely-dangling