Add skeleton docs/patterns.md with type-checked companion file

Introduces a patterns documentation page for common MCP Apps recipes.
The skeleton includes TODO sections for: perceived latency, iframe/MCP Apps
coexistence, authenticated calls, private tools, theme changes, fullscreen,
host styling, data persistence, OpenAI migration, and error handling.

- Add `docs/patterns.md` to `projectDocuments` in `typedoc.config.mjs`
- Add `docs/patterns.ts` companion file with region-delimited code stubs
- Include `docs/**/*.ts` in `tsconfig.json` for type-checking
- Document the standalone docs pattern in `CLAUDE.md`

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

typedoc.config.mjs

@@ -4,7 +4,7 @@ import { OptionDefaults } from "typedoc";
 const config = {
   blockTags: [...OptionDefaults.blockTags, "@description"],
   intentionallyNotExported: ["AppOptions"],
-  projectDocuments: ["docs/quickstart.md"],
+  projectDocuments: ["docs/quickstart.md", "docs/patterns.md"],
   entryPoints: [
     "src/server/index.ts",
     "src/app.ts",