wip: twin floor hook RT_TWIN_FLOOR, keep canon 0.732

- twin floor 0.153 per NOTES 24dd is sens-dependent, default off (env opt-in)
- keeps VLAW TOTAL 0.732 vs bridge 1.594, dual 0.714 (vs 0.193 claim was with corrupted ref)
- next: k-mapping sens/q via campaign.py

dsp/framed_model.cpp

@@ -576,7 +576,15 @@ void FramedDetector::setParams(const std::vector<DetectorBand>& bands) {
         detkernel::twin_apply(c, z.data(), half + 1, out.data());
         for (size_t k = 0; k <= half; k++) {
             r[k] = std::sqrt(out[k].re * out[k].re + out[k].im * out[k].im);
-            r[k] = std::max(r[k], 1e-12f);
+            // Twin gain floor per NOTES 24dd: plugin caps res ≥0.153 @fc1000q1
+            // Our twin 0.0069 at sens24 vs plugin 0.153 (k=22). Floor is
+            // content/sens-dependent; default off (canon). Opt-in via RT_TWIN_FLOOR.
+            static const float twin_floor = []{
+                if (const char* e = getenv("RT_TWIN_FLOOR")) return static_cast<float>(atof(e));
+                return 0.0f;
+            }();
+            if (twin_floor > 0) r[k] = std::max(r[k], twin_floor);
+            else r[k] = std::max(r[k], 1e-12f);
         }
         
         // Store complex response for cascade 529c60