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/engine/master_gain.cpp

@@ -48,4 +48,4 @@ void formatMasterGainLabel(double norm, char* buf, std::size_t len) {
     std::snprintf(buf, len, "%+.1fdB", db);
 }
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine

src/core/instrument/engine/master_gain.h

@@ -55,4 +55,4 @@ double masterGainNormFromLinear(double linear);
 // including the terminator. Pure.
 void formatMasterGainLabel(double norm, char* buf, std::size_t len);
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine

src/core/instrument/engine/pitch_shift.cpp

@@ -431,4 +431,4 @@ AudioSample PitchShifter::processImpl(AudioSample in, const SpliceEvent* linked)
     return static_cast<AudioSample>(out);
 }
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine

src/core/instrument/engine/pitch_shift.h

@@ -227,4 +227,4 @@ private:
                                      // live fade by that rate.
 };
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine

src/core/instrument/engine/velocity_curve.cpp

@@ -269,4 +269,4 @@ bool VelocityCurve::equals(const VelocityCurve& other, double eps) const {
     return true;
 }
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine

src/core/instrument/engine/velocity_curve.h

@@ -168,4 +168,4 @@ private:
     std::vector<VelocityPoint> points_;
 };
 
-}  // namespace reasampler::instrument::engine
+}  // namespace reasampler::instrument::engine