P2.5: decode twin-mask factory (FUN_18056e3e0 = constant fill 2π/(count·SR)) + band LUT apply (FUN_180563a60: level->gain t^γ/power-law); implement in levelpath.cpp, levelpath_check ALL OK

dsp/levelpath.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+// Level-path transcriptions (decomp_funs2.txt + f_*.dis).
+// All offsets are relative to the level-path object (NOT the DSP ctx).
+
+// FUN_180563440: LUT curve build (x = i/1023, linear x^(1/gamma), power-law).
+void lut_curve_eval(void* ctx);
+
+// FUN_18056e3e0: twin-mask factory = constant fill 2π/(count·SR) over 0x400 bins.
+void twin_mask_factory(void* ctx, int band_idx, int n_bins);
+
+// FUN_180563a60: band LUT apply (level -> gain) t^gamma / power-law, 6 bands.
+void band_lut_apply(void* ctx);