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/model/bank_model.h

@@ -214,4 +214,4 @@ private:
     std::vector<Sample> samples_;  // insertion order preserved
 };
 
-} // namespace reasampler::model
+} // namespace reasampler::model