docs: point remix skill to package readmes

Author: brookslybrand

packages/cli/.changes/patch.template-skill-readmes.md

@@ -0,0 +1 @@
+Update the default app template's Remix agent skill to point agents at the full `remix/*` README files shipped in `node_modules/remix`.

template/.agents/skills/remix/SKILL.md

@@ -8,6 +8,19 @@ description: Build and review Remix 3 applications using the `remix` npm package
 Use this skill for end-to-end Remix app work. It should help the agent choose the right layer
 first, reach for the right package, and avoid the most common Remix-specific mistakes.
 
+## Full Package Documentation
+
+This skill is the quick guide. When you need fuller API documentation, examples, or package-specific
+details for a `remix/*` subpath, read that subpath's README next. The published `remix` package
+includes those READMEs next to its generated source files:
+`node_modules/remix/src/<subpath>/README.md`.
+
+Examples:
+
+- `remix/fetch-router` -> `node_modules/remix/src/fetch-router/README.md`
+- `remix/ui/button` -> `node_modules/remix/src/ui/button/README.md`
+- `remix/session/cookie-storage` -> `node_modules/remix/src/session/cookie-storage/README.md`
+
 ## What Remix Is
 
 Remix 3 is a server-first web framework built on Web APIs such as `Request`, `Response`, `URL`,