P4: port framed_render.py model to C++ (FramedDetector: twin-res -> level -> Pchip LUT -> warp -> res^rp gain), replace empirical Detector; tt_base 49.93%->61.45% (single-band); multi-band refs still 100% (model is single-band)

dsp/harness.cpp

@@ -156,10 +156,18 @@ int main(int argc, char* argv[]) {
     }
 
     SpectralProcessor sp(2048, 512);
-    sp.setDetectorParams(
-        static_cast<float>(params.sharpness),
-        static_cast<float>(params.selectivity),
-        static_cast<float>(params.depth));
+    float fc = 500.0f;
+    float q = 1.0f;
+    if (!params.bands.empty()) {
+        for (const auto& b : params.bands) {
+            if (b.on > 0.5f && b.freq > 1.0f) {
+                fc = static_cast<float>(b.freq);
+                q = static_cast<float>(b.q > 0.0f ? b.q : 1.0f);
+                break;
+            }
+        }
+    }
+    sp.setDetectorParams(fc, q);
 
     std::vector<float> left(frames, 0.0f), right(frames, 0.0f);
     encode_ms(left_in.data(), right_in.data(), frames);