Merge ME-import → new RS9k instrument

Repurpose INGEST_IMPORT_MEDIA_EXPLORER to stand up a fresh instrument on
a new track pre-loaded with the imported sound, instead of force-selecting
on the active instance.

src/instrument_drop_win.h

@@ -54,4 +54,24 @@ FxDropTarget resolveFxDropTarget(int screenX, int screenY);
 // undoable.
 bool performInstrumentDrop(MediaTrack* track, const std::string& chunkBase64);
 
+// Add a fresh ReaSampler 9000 instance to `track` and inject `chunkBase64` as its component
+// state. Same all-or-nothing add+inject contract as performInstrumentDrop (rolls the FX back
+// via TrackFX_Delete on inject failure), but does NOT open its own undo block — the caller owns
+// the undo grouping so the whole gesture (track-create + persist + FX-add + inject) collapses to
+// one Ctrl-Z. This is the shared inner half performInstrumentDrop wraps in its own block.
+// Returns true on success, false on any failure. NEVER inserts a timeline item.
+bool loadInstrumentOntoTrack(MediaTrack* track, const std::string& chunkBase64);
+
+// Create a NEW track at the end of the active project's track list, name it `trackName`, add a
+// fresh ReaSampler 9000 instance pre-loaded with `chunkBase64` (RS5k-parity "load into a new
+// sampler"), and return the created track. Does NOT open an undo block — the caller owns the
+// undo grouping (track-create + the caller's bank persist collapse to one Ctrl-Z). All-or-
+// nothing on the instrument side: if the FX add or chunk inject fails, the freshly-created
+// track is deleted before returning nullptr, leaving the project exactly as it was (no orphaned
+// empty track). NEVER inserts a timeline item; the ONLY mutations are one track + one FX
+// instance + that instance's state, all REAPER-undoable. Returns the new track on success,
+// nullptr on any failure.
+MediaTrack* createTrackWithInstrument(const std::string& trackName,
+                                      const std::string& chunkBase64);
+
 }  // namespace reasampler