labels: reader-backed detection, Criterion fix, menu-language fallback

- DetectFn now takes a SectorSource so a parser can inspect a jar's
  central directory in detect() instead of firing on "any BD-J jar".
  dbp/deluxe do the real com/<vendor>/ prefix check up front, so each
  claims only its own discs (foundational for scaling the registry).
- criterion: treat a stream-map value of 0 as unmapped and synthesize a
  real 1-based number, so a 0 can't shadow or collide with a genuine
  stream 1 (with regression tests).
- png_filenames: new Low-confidence, last-resort parser reading menu
  language from {title}_UHD01_{LANG}_Composite artwork; sits below the
  MPLS floor so a real framework parser always wins.
- vocab: add menu_lang() for 639-2/B to 639-2/T menu-token normalization.

src/labels/deluxe.rs

@@ -64,11 +64,15 @@ use crate::sector::SectorSource;
 use crate::udf::UdfFs;
 use std::collections::{HashMap, HashSet};
 
-pub fn detect(udf: &UdfFs) -> bool {
-    // Cheap pre-check at the dir level; the real signal is
-    // `com/bydeluxe/` inside any top-level jar's central directory,
-    // which `parse()` confirms when given a `SectorSource`.
-    jar::has_any_top_level_jar(udf)
+pub fn detect(reader: &mut dyn SectorSource, udf: &UdfFs) -> bool {
+    // The real signal is `com/bydeluxe/` inside a top-level jar's central
+    // directory. With a reader in detect we check it directly (cheap
+    // central-directory scan, no bytecode walk) so this parser claims only
+    // Deluxe discs; `parse()` repeats the check.
+    jar::for_each_jar(reader, udf, |_entry, archive| {
+        jar::has_path_prefix(archive, "com/bydeluxe/").then_some(())
+    })
+    .is_some()
 }
 
 pub fn parse(reader: &mut dyn SectorSource, udf: &UdfFs) -> Option<ParseResult> {