Q-W1 code-review follow-ups: restore 104 trailing newlines, relocate reasampler_uid.h to core/wire, drop ext_keys namespaces shim, add slot_map_tests, golden serialize literals for 4 modules, namespaces.h/pragma-once ordering sweep. 60/60 green.

src/core/instrument/map/trigger_seam.h

@@ -48,4 +48,4 @@ double framesToFadeFraction(std::int64_t fadeFrames, std::int64_t playLength);
 // Rounds to nearest integer frame. Returns 0 when playLength == 0.
 std::int64_t fadeFractionToFrames(double fadeFraction, std::int64_t playLength);
 
-}  // namespace reasampler::instrument::map
+}  // namespace reasampler::instrument::map