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/ctrm.rs

@@ -323,6 +323,11 @@ fn parse_language_streams_text(text: &str) -> Vec<StreamLabel> {
     labels
 }
 
+// NOTE: `parse_menu_base` / `parse_menu_base_text` are defined just below this
+// module and structurally belong above it. They are left in place (with the
+// lint allowed) rather than relocated here — a ~120-line block move that is
+// safer to do as its own focused change than inline.
+#[allow(clippy::items_after_test_module)]
 #[cfg(test)]
 mod tests {
     use super::*;