AACS pipeline reshape + TrueHD metadata + central consts + clippy/fmt clean

- AACS: delete in-lib keydb parser (Step 3); boil-down primitives
  (mk_from_dk/vuk_from_mk/uk_from_vuk) + newtypes; KeySource->get_uk(ctx)+
  ResolveCtx; Unlocker->unlock()->Result<Vid,UnlockError> + AacsCertUnlocker;
  OEM bus-key gate (AacsBusKeyUnavailable); structured ResolutionTrace (Step 4).
- TrueHD: sample-rate from major-sync, Atmos label, 44.1k AU duration.
- consts: central media/format constants module; 17 duplicate const-defs
  centralized (sector/TS-packet/source-packet); mpls stream-entry + category
  codes named.
- clippy --all-targets -D warnings clean (1.86); fmt clean; 2199 lib tests.

src/labels/pixelogic.rs

@@ -536,8 +536,8 @@ mod tests {
     fn parse_token_all_regions_recognized() {
         for region in REGIONS {
             let token = format!("eng_MLP_{}_", region);
-            let l =
-                parse_token_inner(&token, None).expect(&format!("region {} should parse", region));
+            let l = parse_token_inner(&token, None)
+                .unwrap_or_else(|| panic!("region {region} should parse"));
             assert_eq!(l.variant, *region, "region {} should be in variant", region);
         }
     }