TS: Generic BundleEntry<T> and DomainResource<T> for resource-typed fields

[ryukzak]

Depends on #110.

Types like BundleEntry have fields typed as a resource base type (Resource, DomainResource) that acts as a type family with many children. This change detects such fields and emits generic parameters so consumers can narrow the type.

• writer.ts: scan fields for resource type families (via isResourceIdentifier + resourceChildren().length > 0), build <T extends Resource = Resource> generic declarations
• utils.ts: add genericFieldMap param to resolveFieldTsType() for generic field substitution
• profile-slices.ts: add extractResourceTypeFromMatch() helper; compute typedBaseType on SliceDef (e.g. BundleEntry<Patient>); use it in setters, getters, and flat type aliases
• profile.ts: import matched resource types for type discriminator slices

Before:

export interface BundleEntry extends BackboneElement {
    resource?: Resource;
}

export type ExampleTypedBundle_Entry_PatientEntrySliceFlat = BundleEntry;

public setPatientEntry(input?: ... | BundleEntry): this
public getPatientEntry(mode: 'raw'): BundleEntry | undefined

After:

export interface BundleEntry<T extends Resource = Resource> extends BackboneElement {
    resource?: T;
}

export type ExampleTypedBundle_Entry_PatientEntrySliceFlat = BundleEntry<Patient>;

public setPatientEntry(input?: ... | BundleEntry<Patient>): this
public getPatientEntry(mode: 'raw'): BundleEntry<Patient> | undefined

Affected types: BundleEntry<T>, BundleEntryResponse<T>, DomainResource<T>. Default parameter = Resource means unparameterized usage is unchanged.

Tests & examples

• Add compile-time type narrowing tests: access Patient/Organization-specific fields without casts, DomainResource<Patient> contained narrowing, @ts-expect-error for wrong resource type
• Use explicit BundleEntry<Patient> / BundleEntry<Organization> in set/get tests
• Add Patient and Organization to typed bundle test tree shake
• Update snapshots for parameterized setters/getters
• Regenerate R4 and US Core examples with generic type parameters