docs: move typescript-custom-packages under the TypeScript Generation section

It is a TypeScript example; drop the leftover Custom Package Sources header
(a holdover from when the dir was the language-agnostic package-sources).

Author: ryukzak

examples/README.md

@@ -11,6 +11,10 @@ This directory contains working examples demonstrating the capabilities of Atomi
   - Resource creation, base R4 profiles (bodyweight, blood pressure), and bundle composition
   - US Core profiles with type-safe race/ethnicity/birth-sex extensions and observation slicing
 
+- **[typescript-custom-packages/](typescript-custom-packages/)** - Feeding packages from sources other than the registry
+  - `generate.ts` - Runs two input mechanisms: local unpublished StructureDefinitions from disk (`.localStructureDefinitions()`) and a remote TGZ package by URL (`.fromPackageRef()`, SQL-on-FHIR ViewDefinition)
+  - Demonstrates dependency resolution with FHIR R4/R5 core and tree shaking
+
 ### Multi-Language Generation
 
 - **[python/](python/)** - Python/Pydantic model generation with simple requests-based client
@@ -37,12 +41,6 @@ This directory contains working examples demonstrating the capabilities of Atomi
   - Full Maven project structure with post-generation hooks
   - Demonstrates template-driven code generation for any language or format
 
-### Custom Package Sources
-
-- **[typescript-custom-packages/](typescript-custom-packages/)** - Feeding packages from sources other than the registry
-  - `generate.ts` - Runs two input mechanisms: local unpublished StructureDefinitions from disk (`.localStructureDefinitions()`) and a remote TGZ package by URL (`.fromPackageRef()`, SQL-on-FHIR ViewDefinition)
-  - Demonstrates dependency resolution with FHIR R4/R5 core and tree shaking
-
 ### On-the-Fly Generation
 
 These examples pull packages from the FHIR registry and generate types on-the-fly (generated types are gitignored and regenerated on CI).