Fix drag-out losing audio and FX-container drops losing the capture; re-home ingest under shell/actions

src/core/ui/drag_out.cpp

@@ -48,4 +48,11 @@ PathList assemblePathList(const std::vector<ResolvedSample>& resolved) {
     return out;
 }
 
+OsHandoff decideOsHandoff(const std::vector<std::string>& paths) {
+    OsHandoff out;
+    out.startOsDrag = !paths.empty();
+    out.releaseInternalDrag = out.startOsDrag;
+    return out;
+}
+
 } // namespace reasampler::ui

src/core/ui/drag_out.h

@@ -69,4 +69,19 @@ struct PathList {
 // exact-string — the shell normalizes case/slashes upstream if it wants Windows-style dedup.
 PathList assemblePathList(const std::vector<ResolvedSample>& resolved);
 
+// --- OS hand-off ordering -----------------------------------------------------
+
+// The two side effects the shell performs when a drag crosses out of REAPER. They are ONE
+// decision, not two: winding the internal drag down (release capture, clear drag state) for a
+// hand-off that then cannot happen consumes the gesture — the user sees a drag that silently
+// did nothing and drags again. Never release without starting.
+struct OsHandoff {
+    bool startOsDrag = false;         // hand `paths` to the OS drag initiator
+    bool releaseInternalDrag = false; // first wind down mouse capture + panel drag state
+};
+
+// Decides the hand-off from the assembled path list. Empty (everything stale/unresolvable)
+// means the internal drag stays live rather than dying half-torn-down.
+OsHandoff decideOsHandoff(const std::vector<std::string>& paths);
+
 } // namespace reasampler::ui