Remove Raycast extension (extracted to separate repo) (#45)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wham <448809+wham@users.noreply.github.com>

Author: Copilot

.github/prompts/compile-raycast.prompt.md

@@ -18,10 +18,6 @@ GitHub Brain complements (but does not replace) the [official GitHub MCP server]
 
 ![](./docs/pull.png)
 
-GitHub Brain also includes a Raycast extension:
-
-![](./docs/raycast.png)
-
 GitHub Brain is [programmed in Markdown](https://github.blog/ai-and-ml/generative-ai/spec-driven-development-using-markdown-as-a-programming-language-when-building-with-ai/).
 
 ## Installation
@@ -167,16 +163,6 @@ Add to the VS Code MCP configuration file:
 
 Merge with existing `servers` if present.
 
-## Raycast Extension
-
-Run the Raycast extension with:
-
-```sh
-scripts/raycast
-```
-
-The extension uses the MCP server to search GitHub data.
-
 ## Development
 
 `scripts/run` builds and runs `github-brain` with the checkout directory as home `-m` (database in `db/`, config in `.env`).