feat(cw): port Morse Expert 1.15 CW decoder engine (feature:cw compiles)

Full port of the CW/Morse decoder from Morse Expert 1.15
(com.ve3nea.morse_expert), preserving obfuscated class names and logic.
Ads (gms.ads), billing (BillingClient), and library code were removed per
user; SettingsActivity deferred to Compose integration.

Ported modules:
- pas.*: decoder engine interface + JNI (libnativedecoderjni.so, armeabi-v7a)
- k3.*: FFT library (pseudo-enum q rewritten from smali; sun.misc stubs
  for Unsafe/Cleaner since Android lacks them; FFT path uses float[] branch)
- i3.*, g3.*, j3.*, s.*, d1.AbstractC1518b: DSP/sin-cos tables (long[] tables
  f/f11589g restored from smali)
- H2.a/b: audio capture + decode control core (jadx catch-block illusions
  cleaned per smali; recording try/catch restored around write block)
- J2.a/b: waterfall OpenGL renderer + palette (r10 = anchor color per smali)
- E2.g: waterfall touch frequency picker (height = ScaleView per smali)
- B0.b/B.RunnableC0001b: status-bar + decoded-text UI runnables (real
  constructors recovered from smali)
- MainActivity → controller class (Activity injected; immersive status bar
  inlined); C1646n trimmed to view holder; D.n keeps waterfall texture case
- F2.a: text selection menu (Save/Share)

Verified: :feature:cw:compileDebugJavaWithJavac BUILD SUCCESSFUL.

feature/cw/src/main/java/k3/c.java

@@ -0,0 +1,42 @@
+package k3;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+/* loaded from: classes.dex */
+public abstract class c {
+
+    /* renamed from: a, reason: collision with root package name */
+    public static final ExecutorService f12093a;
+
+    /* renamed from: b, reason: collision with root package name */
+    public static ExecutorService f12094b;
+    public static final int c;
+
+    /* renamed from: d, reason: collision with root package name */
+    public static final long f12095d;
+
+    /* JADX WARN: Type inference failed for: r1v0, types: [java.lang.Object, k3.a] */
+    static {
+        ExecutorService newCachedThreadPool = Executors.newCachedThreadPool(new b(new a()));
+        f12093a = newCachedThreadPool;
+        f12094b = newCachedThreadPool;
+        c = Runtime.getRuntime().availableProcessors();
+        f12095d = 100000L;
+    }
+
+    public static Future a(Runnable runnable) {
+        if (f12094b.isShutdown() || f12094b.isTerminated()) {
+            f12094b = f12093a;
+        }
+        return f12094b.submit(runnable);
+    }
+
+    public static void b(Future[] futureArr) throws InterruptedException, java.util.concurrent.ExecutionException {
+        // smali: 无 catch 直接向上抛 -> Java 声明 throws(忠实表达)
+        for (Future future : futureArr) {
+            future.get();
+        }
+    }
+}