fix(cw): repair FFT pipeline (NaN twiddle table + dead cond_22 path)

The waterfall showed mirrored/upside-down garbage because the FFT
never produced a valid spectrum:
1. g3.c.f() (high-precision sin) had its quadrant-0 case mangled by
   jadx into a nested-if that returned NaN for small angles - the
   twiddle factor table ended up with 329/1024 NaN entries.
   Restored the smali switch: case0->g(), case1->c(), case2->-g(),
   case3->-c().
2. i3.d.k() routed the runtime FFT (a5==0, single-thread path) into
   the else of if(a5!=1) instead of if(a5!=0), so the FFT never ran
   and the output stayed in the time domain (peak at bin 357 for a
   669Hz tone instead of bin 86).

Verified with a JVM harness (static-block tables + pure-tone inputs):
200Hz->bin26, 400Hz->bin51, 669Hz->bin86, 1000Hz->bin128, all exact.
Twiddle table NaN count: 329 -> 0.

feature/cw/src/main/java/g3/c.java

@@ -455,21 +455,23 @@ public abstract class c {
             if (z3) {
                 i4 ^= 2;
             }
+            // smali 证实: f() = sin(象限 switch!):
+            //   case 0 -> g(d5,0)(sin(0-π/2))
+            //   case 1 -> c(d5,0)(sin(π/2-π) = cos(余角))
+            //   case 2 -> -g(d5,0)(sin(π-3π/2) = -sin(余角))
+            //   case 3 -> -c(d5,0)(sin(3π/2-2π) = -cos(余角))
+            // jadx 畸形嵌套 if 把 case 0 还原成 return NaN(小角度全 NaN!),
+            // 且 case 1/2/3 全走 g() —— 旋转因子表 329 个 NaN + 频谱错乱的根源!
             if (i4 == 0) {
-                if (i4 != 1) {
-                    if (i4 != 2) {
-                        if (i4 != 3) {
-                            return Double.NaN;
-                        }
-                        g4 = c(d5, d7);
-                    } else {
-                        g4 = g(d5, d7);
-                    }
-                    return -g4;
-                }
+                return g(d5, d7);
+            }
+            if (i4 == 1) {
                 return c(d5, d7);
             }
-            return g(d5, d7);
+            if (i4 == 2) {
+                return -g(d5, d7);
+            }
+            return -c(d5, d7);
         }
         d7 = d6;
         // jadx 还原不完整(smali 650 行, jadx 只还原 63 行); f() 未被任何代码调用(死代码),

feature/cw/src/main/java/i3/d.java

@@ -1211,7 +1211,8 @@ public final class d {
                                 throw null;
                             }
                         }
-                    } else {
+                    }
+                } else {
                         // smali cond_22(a5==0, k=1 时运行时路径!): 单线程 FFT + 后处理
                         // jadx 原把这段错塞进 if(i8!=1) 的 else(死代码), a5==0 的 else 是幻觉(throw null)
                         int i26 = this.f11700a;
@@ -1264,4 +1265,3 @@ public final class d {
             }
         }
     }
-}