Add deterministic, CPU-only removal of the visible Doubao "豆包AI生成" mark and
a position-agnostic region eraser for any other visible watermark/logo.
- doubao_engine.py: locate (geometry, scales with width) + polarity-aware
white-top-hat glyph mask + cv2 inpaint; coverage-gated detection and a
dense-text safety guard. No GPU, ~30ms.
- region_eraser.py + `erase` command: inpaint arbitrary --region box(es).
Default cv2 backend (no deps); optional big-LaMa via onnxruntime (`lama`
extra, Carve/LaMa-ONNX, model downloaded on first use, never bundled).
- cli `visible --mark auto|gemini|doubao`: auto routes by detector confidence.
- tests for both engines; seed previously-unseeded CLI image fixtures to stop
the Doubao detector flaking on random corners.
- .gitignore: doubao_capture/{seeds,captures} scratch (alpha-map calibration).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
test-user