docs(readme): restore image-1.png and fix broken screenshot link

Raw GitHub URL 404'd since fbbc5e8 removed the file. Restore from 37b1245
and switch both READMEs to relative path (./image-1.png).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: brycewang-stanford

README.md

@@ -37,7 +37,7 @@ Multilevel, frontier, and econ-trinity passed independent oracle + code-reviewer
 
 **Previously in v0.8.0**: **Spatial Econometrics Full-Stack** — 38 new API symbols covering weights, ESDA, ML/GMM regression, GWR/MGWR, and spatial panel. Plus: local projections, GARCH, ARIMA, BVAR, LiNGAM, GES, optimal matching, cardinality matching, RIF decomposition, mediation sensitivity, Cox frailty, AFT survival, rdpower, survey calibration. **60+ new functions across 10 domains.**
 
-![StatsPAI interactive plot editor](https://raw.githubusercontent.com/brycewang-stanford/statspai/main/image-1.png)
+![StatsPAI interactive plot editor](./image-1.png)
 
 > Built by the team behind [CoPaper.AI](https://copaper.ai) · Stanford REAP Program
 

README_CN.md

@@ -31,7 +31,7 @@ StatsPAI 是一个**面向 AI Agent** 的 Python 因果推断与应用计量经
 
 **v0.6 新功能**：`sp.interactive(fig)` —— 类似 Stata Graph Editor 的 WYSIWYG 图表编辑器，支持 29 种学术主题、实时预览、自动生成可复现代码。
 
-![StatsPAI 交互式图表编辑器](https://raw.githubusercontent.com/brycewang-stanford/statspai/main/image-1.png)
+![StatsPAI 交互式图表编辑器](./image-1.png)
 
 > 由 [CoPaper.AI](https://copaper.ai) 团队构建 · 斯坦福 REAP 项目