feat: 添加CSV文件比较可视化功能和pixi配置更新

主要改动：
1. 新增CSV文件比较可视化功能：
   - 添加了src/visualization/comparison.py模块，支持比较两个CSV文件并使用不同颜色可视化
   - 支持命令行和API两种使用方式
   - 可生成静态图像或启动交互式查看器
   - 支持自定义标签、模型和UMAP参数

2. 更新pixi.toml配置：
   - 添加linux-64平台支持
   - 增加多个依赖项：ipykernel, anywidget, rdkit, selfies, fastapi, fastmcp, docker等
   - 完善依赖版本约束

3. 更新README.md文档：
   - 添加CSV文件比较可视化功能说明和使用示例

pixi.toml

@@ -2,9 +2,23 @@
 authors = ["lingyuzeng <pylyzeng@gmail.com>"]
 channels = ["conda-forge"]
 name = "embedding_atlas"
-platforms = ["osx-arm64"]
+platforms = ["linux-64","osx-arm64"]
 version = "0.1.0"
 
 [tasks]
 
 [dependencies]
+python = "3.12.*"
+ipykernel = "*"
+anywidget = "*"
+notebook = "*"
+rdkit = "*"
+pandas = "*"
+selfies = "==2.1.1"
+fastapi = ">=0.111"
+uvicorn = "*"
+fastmcp = ">=2.11"
+docker = ">=7.1"
+httpx = ">=0.27"
+pydantic-settings = ">=2.2"
+matplotlib = "*"