Version 1.0: VLAW parameterization + detector cascade

- Implemented exact ln/exp2 infrastructure (log2_ln.hpp/cpp)
- Parameterized VLAW α/β/c by (fc, q, sens) configuration
- Implemented real RFFT for FIR construction
- Fixed VLAW parameterization for dual group (3.455 → 0.764 dB)
- Added detector cascade 529c60 (Haar smoothing, magnitude, peak processing)
- TOTAL error: 0.870 dB (vs bridge baseline 1.594 dB)

Results:
- t1kq: 0.618 dB (bridge: 0.226 dB)
- t1k: 0.938 dB (bridge: 1.801 dB) ✓ better
- al: 0.727 dB (bridge: 0.638 dB)
- res: 0.284 dB (bridge: 0.628 dB) ✓ better
- dual: 0.764 dB (bridge: 0.726 dB)
- comb: 3.000 dB (bridge: 10.149 dB) ✓ better

dsp/fn529fe0.hpp

@@ -18,6 +18,57 @@
 // (level = am/res) but fed through the structural chain instead of the LUT bridge.
 namespace fn529fe0 {
 
+// ---- Detector cascade 529c60 -----------------------------------------------
+
+// Per-band persistent state for the detector cascade.
+// The accumulator (5407a8 in the binary) persists between frames,
+// creating exponential smoothing: acc_{t+1} = w * acc_t + (1-w) * curve_t
+struct CascadeState {
+    std::vector<float> accumulator;  // nbin elements, persists between frames
+};
+
+// One Haar smoothing pass (kernel [0.25, 0.5, 0.25]).
+// Decoded from 529c60 Haar loop (BLOCKMAP 24mm14, lines 35-74).
+// Net effect: b[i] = 0.25*b[i-1] + 0.5*b[i] + 0.25*b[i+1] (wavelet smooth).
+void haar_one_pass(float* b, size_t n);
+
+// Haar smoothing: iterate Haar passes n_iters times.
+void haar_smooth(float* data, size_t n, int n_iters);
+
+// Compute |z| from interleaved complex state (Phase 1, 16140).
+// in: interleaved [re0,im0,re1,im1,...], out: [mag0,mag1,...]
+void compute_magnitudes(const float* complex_state, float* magnitudes, size_t nbin);
+
+// Full detector cascade 529c60 (decoded from assembly, 24mm14).
+//
+// Pipeline:
+//   1. compute_magnitudes: complex → |z|  (skipped if is_magnitude=true)
+//   2. haar_smooth: |z| → smoothed curve
+//   3. peak = max(curve)
+//   4. sin_peak = sin(param*30 - 90) * 0.115129 * peak
+//   5. curve[i] = max(curve[i], sin_peak)
+//   6. w = -log10(pow(50, ratio*0.001) * ratio*0.001)
+//   7. acc[i] = acc[i] * w + curve[i] * (1-w)
+//   8. bands_curve = acc (memcpy)
+//
+// State (CascadeState) must persist between frames per-band.
+// When is_magnitude=true, input_data is already |z| (nbin floats),
+// not interleaved complex (2*nbin floats).
+void cascade_detect(
+    const float* input_data,       // input: complex (2*nbin) or magnitude (nbin)
+    float* bands_curve,            // in/out: bands_curve (nbin), overwritten
+    CascadeState& state,           // per-band persistent state
+    size_t nbin,                   // N/2+1 (2049 for N=4096@48k)
+    int n_iters,                   // Haar iterations (ctx[0x1b0], default 2)
+    float sin_peak_param,          // ctx[0x54087c] sin modulation parameter
+    float ctx24,                   // ctx[0x24] (unknown, default 10.0)
+    int ctx1a0,                    // ctx[0x1a0] (init=1)
+    int ctx1ac,                    // ctx[0x1ac] (init=4)
+    bool is_magnitude = false      // true = input_data is already |z|, skip Phase 1
+);
+
+// ---- Legacy structural chain functions --------------------------------------
+
 // All per-bin buffers are length nbin = nfft/2+1 (internal grid).
 // IIR stage: y[i] = A[i]*acc + B[i]*x[i]; acc=y (first-order leaky, like leveltrack).
 void iir1(float* x, const double* A, const double* B, size_t nbin, double acc0);