feat(mental-health): make the screener score rows server-owned COMPUTED measurements

Each completed PHQ-9 / GAD-7 administration already projects its total
onto a PHQ9_SCORE / GAD7_SCORE measurement row (unit score, linked via
externalId assessment:<id>). Those rows were attributed MANUAL — a
client-writable source. The projection is a server-derived value, so it
now writes source COMPUTED, the same server-owned source RECOVERY_SCORE
uses: no client write surface can attribute COMPUTED, so a forged score
trend point cannot enter through the measurement POST. Migration 0225
re-attributes the existing assessment-linked projection rows; a score a
user typed into the generic measurement form keeps MANUAL. OpenAPI
description updated and the spec regenerated.

src/lib/validations/__tests__/measurement.test.ts

@@ -470,6 +470,24 @@ describe("measurement validation", () => {
       }
     });
 
+    it("rejects a COMPUTED-attributed screener score row on a client write", () => {
+      // v1.27.6 — the mental-wellbeing screener projects each completed
+      // administration onto a COMPUTED-source PHQ9_SCORE / GAD7_SCORE row
+      // (the RECOVERY_SCORE precedent). COMPUTED is not client-attributable,
+      // so a client can never mint a server-owned score trend point.
+      for (const type of ["PHQ9_SCORE", "GAD7_SCORE"]) {
+        const parsed = createMeasurementSchema.safeParse({
+          type,
+          value: 5,
+          measuredAt: "2026-06-02T12:00:00Z",
+          source: "COMPUTED",
+        });
+        expect(parsed.success, `expected COMPUTED ${type} to be rejected`).toBe(
+          false,
+        );
+      }
+    });
+
     it("accepts the client-writable sources MANUAL and APPLE_HEALTH", () => {
       for (const source of ["MANUAL", "APPLE_HEALTH"]) {
         const parsed = createMeasurementSchema.safeParse({