Add slide and rotate interactive captcha solvers

New solver subsystem with independent models:
- GapDetectorCNN (1x128x256 grayscale → sigmoid) for slide gap detection
- RotationRegressor (3x128x128 RGB → sin/cos via tanh) for rotation angle prediction
- SlideSolver with 3-tier strategy: template match → edge detect → CNN fallback
- RotateSolver with ONNX sin/cos → atan2 inference
- Generators, training scripts, CLI commands, and slide track utility

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

solvers/__init__.py

@@ -0,0 +1,17 @@
+"""
+验证码求解器包
+
+提供两种交互式验证码求解器：
+- SlideSolver: 滑块验证码求解 (OpenCV 优先 + CNN 兜底)
+- RotateSolver: 旋转验证码求解 (ONNX sin/cos 回归)
+"""
+
+from solvers.base import BaseSolver
+from solvers.slide_solver import SlideSolver
+from solvers.rotate_solver import RotateSolver
+
+__all__ = [
+    "BaseSolver",
+    "SlideSolver",
+    "RotateSolver",
+]