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/graphics.py

@@ -2049,6 +2049,69 @@ class Paint(Stub):
     def descent(self) -> float:
         return self._text_size * 0.2
 
+    def setStrokeCap(self, cap):
+        self._stroke_cap = cap
+
+    def getStrokeCap(self):
+        return getattr(self, '_stroke_cap', 0)
+
+    def setStrokeJoin(self, join):
+        self._stroke_join = join
+
+    def getStrokeJoin(self):
+        return getattr(self, '_stroke_join', 0)
+
+    def setStrokeMiter(self, miter):
+        self._stroke_miter = miter
+
+    def getStrokeMiter(self):
+        return getattr(self, '_stroke_miter', 4.0)
+
+    def getTextBounds(self, text, start, end, bounds):
+        if hasattr(self, '_text_size'):
+            w = len(text[start:end]) * self._text_size * 0.5
+            h = self._text_size
+        else:
+            w = len(text[start:end]) * 12
+            h = 24
+        bounds.left = 0
+        bounds.top = -int(h * 0.8)
+        bounds.right = int(w)
+        bounds.bottom = int(h * 0.2)
+
+    def setBlendMode(self, blendmode):
+        self._blend_mode = blendmode
+
+    def getBlendMode(self):
+        return getattr(self, '_blend_mode', None)
+
+    def setLetterSpacing(self, letterSpacing):
+        self._letter_spacing = letterSpacing
+
+    def getLetterSpacing(self):
+        return getattr(self, '_letter_spacing', 0.0)
+
+    def setFontFeatureSettings(self, settings):
+        self._font_feature_settings = settings
+
+    def getFontFeatureSettings(self):
+        return getattr(self, '_font_feature_settings', None)
+
+    def setHinting(self, mode):
+        self._hinting = mode
+
+    def getHinting(self):
+        return getattr(self, '_hinting', 2)  # HINTING_ON
+
+    def setFakeBoldText(self, fakeBoldText):
+        self._fake_bold_text = fakeBoldText
+
+    def isFakeBoldText(self):
+        return getattr(self, '_fake_bold_text', False)
+
+    def hasGlyph(self, string):
+        return len(string) > 0
+
 
 # ═══════════════════════════════════════════════════════════════
 # Bitmap