fix(medications): swallow concurrent-projection duplicates in intake backfill

PR #191 added a today-window backfill to /api/medications/intake. The
v1.4.39.4 dashboard symmetry fix wires the exact same projection into
/api/dashboard/summary, which means two parallel routes can now race
the same (userId, medicationId, scheduledFor, REMINDER) row between
their existence probes and createMany calls. The @@unique on
(userId, medicationId, scheduledFor, source) is the structural
backstop; without skipDuplicates: true the loser of that race would
surface a constraint violation as a 5xx.

Pair the createMany with skipDuplicates: true so Postgres swallows the
rejected rows and both routes still return 2xx. Matches the same flag
the dashboard route ships with.

src/app/api/medications/intake/route.ts

@@ -146,6 +146,15 @@ export const GET = apiHandler(async (request: NextRequest) => {
           // keeps the doctor-report + analytics filters byte-stable.
           source: "REMINDER",
         })),
+        // v1.4.39 W-SERVER-FIX-2 — paired with the schema-level
+        // @@unique([userId, medicationId, scheduledFor, source]). A
+        // concurrent dashboard-summary hit (the second route that now
+        // runs the same projection) can race a duplicate row in
+        // between this route's existence probe and createMany; the
+        // flag tells Postgres to swallow the rejected rows so the
+        // request still returns 2xx. The unique constraint is the
+        // structural backstop, this is the defense-in-depth.
+        skipDuplicates: true,
       });
     }