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/ui/component_geometry.cpp

@@ -105,4 +105,4 @@ int waveformColumnCount(const KitBox& box) {
     return w > 0 ? w : 0;
 }
 
-} // namespace reasampler::ui
+} // namespace reasampler::ui