Summary

• Add US Core IG profile generation (Patient, Observation vitals/BP/bodyweight, Race/Ethnicity/Sex/TribalAffiliation/InterpreterNeeded extensions)
• Refactor profile generation: extract profile-slices, profile-extensions, profile-validation modules
• Add constrained choice detection and deduplicate extensions by canonical URL
• Add writer infrastructure: ifElseChain, lineWidth, naming helpers
• Split from()/apply() factory methods
  • from(resource) — validates meta.profile + runs validate(), throws on errors
  • apply(resource) — stamps meta.profile without validation, for incremental construction
• Multi-form extension setters — accept flat input, profile instance, or raw FHIR Extension
• Extension getters with overloaded mode: flat (typed object), profile (profile instance), raw (FHIR Extension)
• Unify slice and extension getter/setter API with overloaded mode parameter (flat/raw/profile/extension)
• Remove toProfile(), combine imports by module, remove dead helpers
• Return { errors, warnings } from validate() instead of string[]
  • Extensible binding mismatches reported as warnings
  • Must-support field population reported as warnings (non-required fields only)
• Update docs, posts, and README for new API shape

Before — from() was a simple wrapper without validation:

const profile = observation_bodyweightProfile.from(obs);

After — from() validates, apply() stamps without validation:

const profile = USCorePatientProfile.from(obs);   // throws if meta.profile missing or validate() errors
const profile = USCorePatientProfile.apply(obs);   // stamps meta.profile, no validation

Before — extension setters accepted only one form:

patient.setRace(raceExtension);

After — multi-form setters accept flat input, profile instance, or raw Extension:

patient.setRace({ ombCategory: { code: "2028-9" }, text: "Asian" });       // flat input
patient.setRace(USCoreRaceExtensionProfile.create({ ... }));                // profile instance
patient.setRace({ url: "http://.../us-core-race", extension: [...] });      // raw Extension

After — extension getters with mode overloads:

patient.getRace();           // flat: { ombCategory: ..., text: "Asian" }
patient.getRace("profile");  // USCoreRaceExtensionProfile instance
patient.getRace("raw");      // raw FHIR Extension

Before — validate() returned a flat error array, no must-support awareness:

const errors: string[] = bp.validate();

After — structured result with errors and warnings:

const { errors, warnings } = bp.validate();
// errors: ["observation_bp: required field 'effective' is missing"]
// warnings: ["observation_bp: must-support field 'dataAbsentReason' is not populated"]

Before — separate getter methods per mode:

bp.getSystolicBP();     // flat
bp.getSystolicBPRaw();  // raw

After — overloaded single getter:

bp.getSystolicBP();       // flat (default)
bp.getSystolicBP("raw");  // raw FHIR element