TS: example demo for inherited base-required field validation

[ryukzak]

Follow-up to #166. Adds a behaviour-level demo that runs the generated profile (not codegen internals) to lock in inherited base-required field validation.

Bundle.type is required by base R4 Bundle (1..1). The ExampleTypedBundle profile differential only slices entry — it never re-states type. The test builds a valid bundle, drops type, and asserts validate() reports it as missing, then clears once set:

const bundle = ExampleTypedBundleProfile.create({ type: "collection" }).setPatientEntry({ resource: patient });
expect(bundle.validate().errors).toEqual([]);

delete (bundle.toResource() as { type?: unknown }).type;
expect(bundle.validate().errors).toEqual(["ExampleTypedBundle: required field 'type' is missing"]);

bundle.setType("collection");
expect(bundle.validate().errors).toEqual([]);

• examples/local-package-folder/profile-inherited-required.test.ts: new demo.
• Behaviour-level (runs target code), so it survives the per-type validator redesign in TS: generate per-type validate() functions and have profile validators delegate to them #169 that replaces the underlying mechanism.

Verified via make test-local-package-folder-example: regenerate ✅, typecheck ✅, 15/15 tests pass.