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/util/file_bytes.cpp

@@ -18,4 +18,4 @@ std::vector<std::uint8_t> readFileBytes(const std::string& path) {
     return bytes;
 }
 
-}  // namespace reasampler::util
+}  // namespace reasampler::util