Add example agent tool preview (#28984)

This PR adds an example of rendering previews for tools using the new
Agent ToolCard style.

![CleanShot 2025-04-17 at 13 03
12@2x](https://github.com/user-attachments/assets/d4c7d266-cc32-4038-9170-f3e070fce60e)

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

Cargo.lock

@@ -703,6 +703,7 @@ dependencies = [
  "assistant_tool",
  "chrono",
  "collections",
+ "component",
  "feature_flags",
  "futures 0.3.31",
  "gpui",
@@ -711,6 +712,7 @@ dependencies = [
  "itertools 0.14.0",
  "language",
  "language_model",
+ "linkme",
  "open",
  "project",
  "rand 0.8.5",