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

tests/test_drag_out.cpp

@@ -221,6 +221,52 @@ static void testMixedTallies() {
     CHECK(l.skippedDuplicate == 1);
 }
 
+// --- OS hand-off ordering -----------------------------------------------------
+//
+// The drag-out-lands-without-audio regression: the shell used to wind its internal drag down
+// (release capture, clear drag state) BEFORE checking whether the payload had resolved to any
+// on-disk file. A payload that resolved to nothing therefore consumed the gesture — the drag
+// died half-torn-down and the user saw a drop with no audio and dragged again. The two side
+// effects are one decision; these pin that.
+
+// Nothing draggable -> hand off nothing AND keep the internal drag alive.
+static void testEmptyPathsHandsOffNothingAndKeepsInternalDrag() {
+    const OsHandoff h = decideOsHandoff({});
+    CHECK(!h.startOsDrag);
+    CHECK(!h.releaseInternalDrag);
+}
+
+// A resolvable payload -> release the internal drag, then start the OS drag.
+static void testResolvablePayloadHandsOff() {
+    const OsHandoff one = decideOsHandoff({"C:/proj/bank/a.wav"});
+    CHECK(one.startOsDrag);
+    CHECK(one.releaseInternalDrag);
+    const OsHandoff many = decideOsHandoff({"a.wav", "b.wav", "c.wav"});
+    CHECK(many.startOsDrag);
+    CHECK(many.releaseInternalDrag);
+}
+
+// The coupling itself: releasing without starting is the defect, so it must be unreachable
+// for every input the assembler can produce.
+static void testNeverReleasesWithoutStarting() {
+    const std::vector<std::vector<std::string>> inputs = {
+        {}, {"a.wav"}, {"a.wav", "b.wav"}, {""},
+    };
+    for (const std::vector<std::string>& in : inputs) {
+        const OsHandoff h = decideOsHandoff(in);
+        CHECK(!(h.releaseInternalDrag && !h.startOsDrag));
+    }
+}
+
+// End to end through the assembler: a selection whose every entry is stale/unresolvable
+// yields the keep-the-drag verdict, which is exactly the case the shell used to mishandle.
+static void testAllSkippedSelectionKeepsInternalDrag() {
+    const PathList l = assemblePathList({missing("g1.wav"), unresolved()});
+    const OsHandoff h = decideOsHandoff(l.paths);
+    CHECK(!h.startOsDrag);
+    CHECK(!h.releaseInternalDrag);
+}
+
 int main() {
     testInsidePanelStaysInternal();
     testLeavingClientAreaIsOsDrag();
@@ -244,6 +290,11 @@ int main() {
     testAllSkippedYieldsEmpty();
     testMixedTallies();
 
+    testEmptyPathsHandsOffNothingAndKeepsInternalDrag();
+    testResolvablePayloadHandsOff();
+    testNeverReleasesWithoutStarting();
+    testAllSkippedSelectionKeepsInternalDrag();
+
     if (g_fail == 0) std::printf("All tests passed.\n");
     return g_fail ? 1 : 0;
 }