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/wire/instrument_drop.cpp

@@ -1,12 +1,12 @@
 // instrument_drop — pure implementation. See instrument_drop.h.
 // NO REAPER / SWELL / VST3 SDK / vendor. Reuses sample_map's ComponentState serializer and
-// the SDK-free UID macros (vst/reasampler_uid.h).
+// the SDK-free UID macros (core/wire/reasampler_uid.h).
 
 #include "core/wire/instrument_drop.h"
 
 #include <cstdio>
 
-#include "shell/instrument/reasampler_uid.h"  // REASAMPLER_ACTIVE_UID_* — the FROZEN, channel-selected class UID
+#include "core/wire/reasampler_uid.h"  // REASAMPLER_ACTIVE_UID_* — the FROZEN, channel-selected class UID
 #include "core/instrument/map/sample_map.h"      // ComponentState + serializeComponentState (the SHARED writer)
 
 namespace reasampler::wire {
@@ -106,4 +106,4 @@ bool infoNamesFxHotspot(const std::string& info) {
     return startsWith("fx_") || startsWith("tcp.fx") || startsWith("mcp.fx");
 }
 
-}  // namespace reasampler::wire
+}  // namespace reasampler::wire