Add Starlight documentation site structure

- Created comprehensive Diátaxis-based documentation
- 53 pages across Tutorials, How-to, Reference, and Explanation
- Custom branding with @astrojs/discovery logo
- Pagefind search integration
- Ready for content population

docs/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "extends": "astro/tsconfigs/strict",
+  "include": [".astro/types.d.ts", "**/*"],
+  "exclude": ["dist"]
+}