feat(core): 扩展 API、完善日志与代码文档规范

- 公开颜色过滤与字符集限制扩展 API，修复宏路径
- 库内打印替换为 tracing 日志，清理遗留废弃代码
- 补充核心逻辑单元测试与 crate 元数据
- 开启 missing_docs 并统一 rustfmt/clippy 格式

ddddocr-core/Cargo.toml

@@ -3,14 +3,16 @@ name = "ddddocr-core"
 version = { workspace = true }
 edition = { workspace = true }
 license = { workspace = true }
+description = "ddddocr-rs 的核心库：引擎无关的 OCR、目标检测与滑块匹配实现"
+keywords = ["ocr", "captcha", "ddddocr", "onnx", "image"]
+categories = ["multimedia::images", "computer-vision"]
+# repository = "https://github.com/<用户名>/<仓库名>"  # 发布前请补充
+readme = "../README.md"
 
 [dependencies]
-ndarray = { workspace = true } # 继承自工作空间
-
+ndarray = { workspace = true }
 base64 = { workspace = true }
-
 image = { workspace = true }
 imageproc = { workspace = true }
-
-thiserror = { workspace = true } # 刚好可以开始接入你需要的标准库错误处理
-tracing={workspace = true}
+thiserror = { workspace = true }
+tracing = { workspace = true }