feat: 全面完善API — 补全核心类方法、存根转真实实现、Exception体系扩展

核心类方法补全:
- Activity: +20方法 (requestWindowFeature, setTitle/getTitle, onKeyDown/onKeyUp, enterPictureInPictureMode, getReferrer, isTaskRoot, navigateUpTo等)
- Fragment: +15方法 (getChildFragmentManager, getParentFragment, requireContext/requireActivity, setMenuVisibility等)
- Intent: +20方法 (getParcelableExtra, setComponent/getComponent, getDataString, getScheme, putExtras等)
- View: +20方法 (setLabelFor, setRotationX/Y, setForeground, setBackgroundTintList等)
- KeyEvent: +7方法 (getCharacters, isSystem, isPrintingKey, isModifierKey, startTracking等)
- Paint: +12方法 (setStrokeCap/Join, getTextBounds, setBlendMode, setLetterSpacing等)
- Notification.Builder: +10方法 (setProgress, setShowWhen, setOnlyAlertOnce, setSound等)

存根转真实实现:
- TrafficStats: 读取 /proc/net/dev 返回真实网络流量
- RecyclerView.Adapter: 观察者模式触发通知
- BaseAdapter: 观察者模式触发通知
- ExifInterface: 使用PIL实现图片翻转/旋转
- Process: 使用os.kill实现进程信号
- FileUtils: 真实文件I/O
- SharedPreferences: 监听器模式
- TelephonyManager.listen: 维护监听器列表
- ScrollView.smoothScrollTo: 更新滚动位置

Exception体系扩展:
- 新增15个Exception/Error类 (ClassNotFoundException, IllegalAccessException, InstantiationException, InvocationTargetException, NoSuchElementException, AssertionError, OutOfMemoryError, StackOverflowError, NoClassDefFoundError, UnsatisfiedLinkError, LinkageError, VerifyError, AbstractMethodError, IncompatibleClassChangeError, ExceptionInInitializerError)

Math/System/Thread/StringBuilder/Integer增强:
- Math: +20方法 (subtractExact, multiplyExact, toIntExact, floorDiv/floorMod, fma等)
- System: getProperties/setProperties/mapLibraryName/getLogger
- Thread: +10方法 (getUncaughtExceptionHandler, getAllStackTraces, getStackTrace, holdLock等)
- StringBuilder: +7方法 (ensureCapacity, trimToSize, setLength, subSequence等)
- Integer: +8静态方法 (compare, compareUnsigned, divideUnsigned, sum, max, min等)

修复:
- app_fragment.py: 使用java.lang.IllegalStateException替代本地定义
- content_intent.py: Intent.setData/getScheme正确从Uri提取scheme
- view_ext.py: KeyEvent继承view.KeyEvent获取所有KEYCODE常量
- __init__.py: 补全Fragment/KeyEvent/MotionEvent/TrafficStats/RecyclerView等导出

统计: 221模块, 3660类, 30826方法, 180217行

android_pyapi/android/widget.py

@@ -1260,28 +1260,48 @@ class RecyclerView(ViewGroup):
             return False
 
         def notifyDataSetChanged(self):
-            pass
+            for observer in getattr(self, '_observers', []):
+                observer.onChanged()
 
-        def notifyItemChanged(self, position: int):
-            pass
+        def notifyItemChanged(self, position, payload=None):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeChanged(position, 1, payload)
 
-        def notifyItemInserted(self, position: int):
-            pass
+        def notifyItemInserted(self, position):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeInserted(position, 1)
 
-        def notifyItemRemoved(self, position: int):
-            pass
+        def notifyItemRemoved(self, position):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeRemoved(position, 1)
 
-        def notifyItemMoved(self, from_position: int, to_position: int):
-            pass
+        def notifyItemMoved(self, fromPosition, toPosition):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeMoved(fromPosition, toPosition, 1)
 
-        def notifyItemRangeChanged(self, position_start: int, item_count: int):
-            pass
+        def notifyItemRangeChanged(self, positionStart, itemCount, payload=None):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeChanged(positionStart, itemCount, payload)
 
-        def notifyItemRangeInserted(self, position_start: int, item_count: int):
-            pass
+        def notifyItemRangeInserted(self, positionStart, itemCount):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeInserted(positionStart, itemCount)
 
-        def notifyItemRangeRemoved(self, position_start: int, item_count: int):
-            pass
+        def notifyItemRangeRemoved(self, positionStart, itemCount):
+            for observer in getattr(self, '_observers', []):
+                observer.onItemRangeRemoved(positionStart, itemCount)
+
+        def registerAdapterDataObserver(self, observer):
+            if not hasattr(self, '_observers'):
+                self._observers = []
+            self._observers.append(observer)
+
+        def unregisterAdapterDataObserver(self, observer):
+            if hasattr(self, '_observers'):
+                try:
+                    self._observers.remove(observer)
+                except ValueError:
+                    pass
 
         def getStateRestorationPolicy(self) -> int:
             return 0
@@ -2068,11 +2088,13 @@ class ScrollView(FrameLayout):
     def arrowScroll(self, direction: int) -> bool:
         return True
 
-    def smoothScrollTo(self, x: int, y: int):
-        self._scroll_position = y
+    def smoothScrollTo(self, x, y):
+        self._scroll_x = x
+        self._scroll_y = y
 
-    def smoothScrollBy(self, dx: int, dy: int):
-        self._scroll_position += dy
+    def smoothScrollBy(self, dx, dy):
+        self._scroll_x = getattr(self, '_scroll_x', 0) + dx
+        self._scroll_y = getattr(self, '_scroll_y', 0) + dy
 
     def pageScroll(self, direction: int) -> bool:
         return True
@@ -2106,11 +2128,13 @@ class HorizontalScrollView(FrameLayout):
     def arrowScroll(self, direction: int) -> bool:
         return True
 
-    def smoothScrollTo(self, x: int, y: int):
-        pass
+    def smoothScrollTo(self, x, y):
+        self._scroll_x = x
+        self._scroll_y = y
 
-    def smoothScrollBy(self, dx: int, dy: int):
-        pass
+    def smoothScrollBy(self, dx, dy):
+        self._scroll_x = getattr(self, '_scroll_x', 0) + dx
+        self._scroll_y = getattr(self, '_scroll_y', 0) + dy
 
     def pageScroll(self, direction: int) -> bool:
         return True
@@ -2795,16 +2819,24 @@ class BaseAdapter(Stub):
         return self.getView(position, convert_view, parent)
 
     def notifyDataSetChanged(self):
-        pass
+        for observer in getattr(self, '_observers', []):
+            observer.onChanged()
 
     def notifyDataSetInvalidated(self):
-        pass
+        for observer in getattr(self, '_observers', []):
+            observer.onInvalidated()
 
-    def registerDataSetObserver(self, observer: Any):
-        pass
+    def registerDataSetObserver(self, observer):
+        if not hasattr(self, '_observers'):
+            self._observers = []
+        self._observers.append(observer)
 
-    def unregisterDataSetObserver(self, observer: Any):
-        pass
+    def unregisterDataSetObserver(self, observer):
+        if hasattr(self, '_observers'):
+            try:
+                self._observers.remove(observer)
+            except ValueError:
+                pass
 
 
 class ArrayAdapter(BaseAdapter):