Migration notice added to README (#178)

Author: jbarry-bdai

README.md

@@ -13,6 +13,29 @@
 [![PyPI - Downloads](https://img.shields.io/pypi/dw/spatialmath-python)](https://pypistats.org/packages/spatialmath-python)
 [![GitHub stars](https://img.shields.io/github/stars/bdaiinstitute/spatialmath-python.svg?style=social&label=Star)](https://GitHub.com/bdaiinstitute/spatialmath-python/stargazers/)
 
+# Repository Migration Notice
+
+> [!IMPORTANT]
+> This repository is moving to the **RAI-Opensource** GitHub organization in **about 2 weeks from April 9, 2026 (UTC)**.
+>
+> The `github.io` page is now at <https://spatialmath-python.rai-inst.com/>.  The old link (`https://bdaiinstitute.github.io/spatialmath-python`) will continue to redirect until repository migration and **then will break**.
+>
+> Current status: **pre-migration**.
+> Migration target org: <https://github.com/RAI-Opensource/spatialmath-python>
+>
+> What to do now:
+>
+> - Immediately: Update any links of `https://bdaiinstitute.github.io/spatialmath-python` to  <https://spatialmath-python.rai-inst.com/>
+>
+>
+> - Watch this repository for the final cutover update and destination repository link.
+> - Plan to update your git remote after the move:
+>
+>   ```bash
+>   git remote set-url origin https://github.com/rai-opensource/spatialmath-python.git
+>   ```
+>
+>
 
 
 <table style="border:0px">
@@ -23,7 +46,7 @@
 A Python implementation of the <a href="https://github.com/petercorke/spatial-math">Spatial Math Toolbox for MATLAB<sup>&reg;</sup></a>
 <ul>
 <li><a href="https://github.com/bdaiinstitute/spatialmath-python">GitHub repository </a></li>
-<li><a href="https://bdaiinstitute.github.io/spatialmath-python">Documentation</a></li>
+<li><a href="https://https://spatialmath-python.rai-inst.com">Documentation</a></li>
 <li><a href=https://github.com/bdaiinstitute/spatialmath-python/discussions/categories/changes>Recent changes</a>
 <li><a href="https://github.com/bdaiinstitute/spatialmath-python/wiki">Wiki (examples and details)</a></li>
 <li><a href="installation#">Installation</a></li>
@@ -32,6 +55,7 @@ A Python implementation of the <a href="https://github.com/petercorke/spatial-ma
 </tr>
 </table>
 
+
 Spatial mathematics capability underpins all of robotics and robotic vision where we need to describe the position, orientation or pose of objects in 2D or 3D spaces.