feat: 大幅增强原生行为 — 修复P0 Bug + 补全核心API

P0 Bug 修复:
- Canvas.drawBitmap 重复定义导致重载丢失 → 合并为*args重载
- String.hashCode() 不可达的第二return → 修复为单return
- File.compareTo() 调用不存在的__cmp__ → 改为显式比较
- HashMap.remove() 逻辑错误 → 区分单参(返回旧值)/双参(返回boolean)

P1 核心行为增强:
- Handler: sendMessage/sendMessageDelayed 现在真正入队异步执行
- Looper: loop() 实现真正的消息循环(按when时间取出到期消息)
- AsyncTask: execute() 在后台线程池执行,完成后主线程回调
- Bundle: 新增12个数组类型put/get方法
- Math.round: 改为Java语义(floor(a+0.5))而非Python银行家舍入
- Thread: currentThread()缓存对象, 新增join/getState/getId/getPriority
- String: 新增strip/repeat/isBlank/lines/subSequence/getChars/chars/formatted/translateEscapes

P2 缺失API补全:
- 新增21个Java标准Exception类 (NullPointerException等)
- View: 新增39个事件处理/监听器/位置尺寸方法
- Activity: 新增33个生命周期/权限/UI方法
- Context: 新增22个文件流/权限/资源/主题方法
- Canvas: 支持 Canvas(Bitmap) 构造函数重载
- __init__.py: __all__ 补全Exception体系和Activity类

android_pyapi/__init__.py

@@ -378,7 +378,7 @@ __all__ = [
     "AccessibilityNodeInfo", "AccessibilityService",
     "AccessibilityServiceInfo",
     "Account", "AccountManager",
-    "ActivityManager",
+    "Activity", "ActivityManager",
     "AlphaAnimation",
     "Animation",
     "Animator", "ValueAnimator", "ObjectAnimator", "AnimatorSet",
@@ -512,6 +512,18 @@ __all__ = [
     "String", "StringBuilder", "StringBuffer",
     "Integer", "Math", "System", "Thread",
     "BigInteger", "BigDecimal",
+    # Java Exception 体系
+    "Throwable", "Exception", "RuntimeException", "Error",
+    "NullPointerException", "IllegalArgumentException", "IllegalStateException",
+    "IndexOutOfBoundsException", "ArrayIndexOutOfBoundsException",
+    "StringIndexOutOfBoundsException", "ClassCastException",
+    "UnsupportedOperationException", "ArithmeticException",
+    "NumberFormatException", "SecurityException",
+    "ConcurrentModificationException", "NegativeArraySizeException",
+    "NoSuchFieldException", "NoSuchMethodException", "InterruptedException",
+    "CloneNotSupportedException", "IllegalMonitorStateException",
+    "IllegalThreadStateException", "EnumConstantNotPresentException",
+    "TypeNotPresentException",
     "SimpleDateFormat", "DecimalFormat",
     "LocalDateTime", "LocalDate", "LocalTime", "Instant", "Duration", "Period",
     "ChronoUnit", "ChronoField", "DayOfWeek", "Month", "ZoneId", "ZoneOffset",