DiscStream::new() replaces open_drive/open_iso/from_reader

A stream is a stream. DiscStream::new() takes reader + title + keys +
batch + format — same pattern as every other stream constructor.

Deleted: open_drive(), open_iso(), from_reader() — these were helper
functions that chained multiple operations. Library provides primitives,
callers decide the sequence.

Removed disc:// case from input() — callers use Drive::open() +
Disc::scan() + DiscStream::new() directly for disc sources.

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 0.10.7 (2026-04-17)
+
+### DiscStream::new()
+- Replaced open_drive(), open_iso(), from_reader() with single new() constructor
+- Stream accepts ContentFormat and sets up demuxer internally
+- Removed disc:// case from input() — callers use primitives directly
+
 ## 0.10.6 (2026-04-16)
 
 ### Docker compatibility