TS: Enhance profile code generation with factory methods, extensions, and pattern values

CLAUDE.md

@@ -7,7 +7,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ```bash
 # Development
 bun install                    # Install dependencies
-bun test                      # Run all tests 
+bun test                      # Run all tests
 bun test --watch              # Run tests in watch mode
 bun test --coverage           # Run tests with coverage
 bun run typecheck             # Type check the codebase
@@ -22,6 +22,19 @@ bun run cli typeschema generate hl7.fhir.r4.core@4.0.1 -o schemas.ndjson
 bun run cli generate typescript -i schemas.ndjson -o ./types
 ```
 
+## Verification
+
+After any code change, run at minimum:
+```bash
+bun run typecheck && bun run lint && bun test
+```
+
+For full verification including example generation and cross-project type checking:
+```bash
+make all
+```
+This runs: tests, lint with auto-fix, and all example generation pipelines (TypeScript R4, CCDA, SQL-on-FHIR, C#, Python, Mustache).
+
 ## Architecture Overview
 
 This is a FHIR code generation toolkit with a **three-stage pipeline**:
@@ -69,6 +82,13 @@ FHIR Package → TypeSchema Generator → TypeSchema Format → Code Generators
 - **Generated code**: Output goes to `generated/` directory
 - **Utilities**: Common functions in `src/utils.ts` and `src/typeschema/utils.ts`
 
+## General Principles
+
+- Bias toward action: start making changes directly. Do not write plan files, explore the entire codebase, or use Task sub-agents unless explicitly asked.
+- Keep changes minimal and focused. Do not over-engineer (no extra abstractions, generics, or variants beyond what was requested). When in doubt, do the simplest thing that works.
+- Only modify files and directories that were explicitly mentioned or are directly required by the change. Do not refactor surrounding code.
+- When asked to review or explain code, explain first before proposing fixes. Do not jump to making changes unless explicitly asked to fix something.
+
 ## Development Guidelines
 
 ### TypeScript Configuration

examples/typescript-r4/__snapshots__/extension-profile.test.ts.snap

@@ -0,0 +1,41 @@
+// Bun Snapshot v1, https://bun.sh/docs/test/snapshots
+
+exports[`Patient with extensions built from profiles 1`] = `
+{
+  "_birthDate": {
+    "extension": [
+      {
+        "url": "http://hl7.org/fhir/StructureDefinition/patient-birthTime",
+        "valueDateTime": "1770-12-17T12:00:00+01:00",
+      },
+    ],
+  },
+  "birthDate": "1770-12-17",
+  "extension": [
+    {
+      "url": "http://hl7.org/fhir/StructureDefinition/patient-birthPlace",
+      "valueAddress": {
+        "city": "Bonn",
+        "country": "DE",
+      },
+    },
+  ],
+  "name": [
+    {
+      "_family": {
+        "extension": [
+          {
+            "url": "http://hl7.org/fhir/StructureDefinition/humanname-own-prefix",
+            "valueString": "van",
+          },
+        ],
+      },
+      "family": "van Beethoven",
+      "given": [
+        "Ludwig",
+      ],
+    },
+  ],
+  "resourceType": "Patient",
+}
+`;