docs: use raw GitHub URLs for README images

Npm renders package READMEs outside the repository tree, so relative image paths can break on the registry page. Point the icon and banner at raw GitHub URLs while leaving the local asset files unchanged.

Author: LEON-gittech

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img src="./.github/open-codexcli-icon.png" alt="Open Codex CLI icon" width="180" />
+  <img src="https://raw.githubusercontent.com/LEON-gittech/codex/main/.github/open-codexcli-icon.png" alt="Open Codex CLI icon" width="180" />
 </p>
 
 <h1 align="center">Open Codex CLI</h1>
@@ -18,7 +18,7 @@
 </p>
 
 <p align="center">
-  <img src="./.github/open-codex-cli-unleashed.png" alt="Open Codex CLI unleashed banner" width="960" />
+  <img src="https://raw.githubusercontent.com/LEON-gittech/codex/main/.github/open-codex-cli-unleashed.png" alt="Open Codex CLI unleashed banner" width="960" />
 </p>
 
 <p align="center">