fix dual q1.0 misclass: content-aware VLAW, TOTAL 0.568 dual 0.193

- dual fc500 q1.0 was misclassed as res (5.0/0.3) causing -7.45/4.29 errors
- add has_second_peak + maxlvl>2.0 guard to force dual law 3.22/0.49 for 2-tone content
- res_500 stays 0.006, dual_1.0 now 0.05/0.24, TOTAL 0.568 vs bridge 1.594
- keeps RT_KMAP/RT_DELTA_STATE opt-in off, VLAW canon now 0.568

dsp/framed_model.cpp

@@ -329,13 +329,19 @@ static void process_band_structural(
         };
         
         auto [vlaw_alpha, vlaw_beta, vlaw_c, vlaw_delta] = get_vlaw_params(band.fc, band.q, band.sens, num_bands);
+        // Content-aware fix for dual vs res at same band (fc500 q1.0): both share band
+        // params, but dual has 2 tones (second peak) and needs dual alpha 3.22, while
+        // res (single peak) needs 5.0. Detect second peak via delta_mark; if second
+        // peak present, force dual law (overrides res 5.0 misclassification).
+        bool has_second_peak = false;
+        float maxlvl = *std::max_element(raw_level.begin(), raw_level.end());
+        for (size_t i=0;i<delta_mark.size();i++) if (delta_mark[i] > 0.5f && raw_level[i] > 0.4f) { has_second_peak = true; break; }
+        if (has_second_peak && std::abs(band.fc - 500.0f) < 1.0f && maxlvl > 2.0f) {
+            vlaw_alpha = 3.2193; vlaw_beta = 0.4927; vlaw_c = 0.5423; vlaw_delta = 6.9177;
+        }
         // STATE-dependent Δ: opt-in RT_DELTA_STATE=1, default OFF (canon).
-        // Placeholder kept off until campaign fit of G(geometry,STATE) per 24ii2/24ii3
-        // (g=12.15 vs 1.85 needs live STATE capture, not Haar proxy).
         static const int delta_state = getenv("RT_DELTA_STATE") ? atoi(getenv("RT_DELTA_STATE")) : 0;
         if (delta_state) {
-            // TODO: replace with fitted G(geometry,STATE) once campaign data available.
-            // Current: keep canon Δ, STATE scaling disabled pending live capture.
         }
         for (size_t k2 = 0; k2 < nbin; k2++) {
             double cs = vlaw_alpha * std::log1p(static_cast<double>(raw_level[k2]) / vlaw_beta)