Upgrade TypeScript to v6

Author: cmoesel

DEPENDENCY_NOTES.md

@@ -3,5 +3,5 @@ The following notes about the app's dependencies should be revisited and resolve
 As of 2026-07-27:
 
 - `@types/node`: Consider updating to `26.x` in the future, but for now `24.x` still has plent of time in LTS.
-- `typescript`: `7.x` removes options deprecated in TypeScript 6 and uses a new native compiler. Upgrade to TypeScript 6 first and then consider updating to v7 if/when other packages (like `eslint`) support it.
+- `typescript`: `7.x` uses a new native compiler without a native API. Libraries like `ts-node` and `typescript-eslint` do not yet support it.
 - `tslog` (test-server only): `5.x` is ESM-only and replaces v4's flat logger settings such as `hideLogPositionForProduction` and `prettyLogTemplate`. Updating will require some migration.

package-lock.json

@@ -89,7 +89,7 @@
     "sinon": "^22.1.0",
     "test-console": "^2.0.0",
     "ts-node": "^10.9.2",
-    "typescript": "^5.9.3",
+    "typescript": "^6.0.3",
     "xml-js": "^1.6.11"
   },
   "dependencies": {

package.json

@@ -39,7 +39,7 @@
     "prettier": "^3.9.6",
     "ts-node": "^10.9.2",
     "tsx": "^4.23.1",
-    "typescript": "^5.9.3",
+    "typescript": "^6.0.3",
     "vitest": "^4.1.10"
   }
 }

test-server/package-lock.json

@@ -328,7 +328,6 @@ function toFhirQuantity(val: CqlQuantity | number, isIntegerOrLong = false): Fhi
     }
   }
   if (isIntegerOrLong) {
-    // @ts-expect-error R4 Quantity type should allow _value for setting id and extension on decimal value
     fq._value = {
       extension: [
         { url: 'http://hl7.org/fhir/StructureDefinition/quantity-precision', valueInteger: 0 }