test(cycle): pin the fixture clock to the suite's clock

Two cycle suites compute their relative day keys with local Date arithmetic
under TZ=UTC while the routes resolve today in the user's zone, falling back
to Europe/Berlin when the fixture sets none. For two hours every evening the
two clocks disagree about the date and every day-of-cycle assertion is off
by one — the suite was red from 22:00 UTC to midnight and green the rest of
the day. The fixtures now carry an explicit UTC timezone so the test's clock
and the route's clock are the same clock at any hour. Reproduced red at
23:07 UTC, green with the pin at 23:19 UTC.

tests/integration/cycle-flow-opens-cycle.test.ts

@@ -70,6 +70,14 @@ beforeEach(async () => {
       username: "cycle-flow",
       email: "cycle-flow@example.test",
       gender: "FEMALE",
+      // The suite runs under TZ=UTC and computes its relative day keys with
+      // local Date arithmetic, i.e. in UTC. The route resolves "today" in the
+      // USER's zone and falls back to Europe/Berlin when none is set - one
+      // hour past 22:00 UTC the two clocks disagree about the date and every
+      // day-of-cycle assertion is off by one. Pinning the fixture zone to UTC
+      // makes the test's clock and the route's clock the same clock at any
+      // hour of the day.
+      timezone: "UTC",
     },
   });
   await loginAs(USER_ID);

tests/integration/cycle-routes.test.ts

@@ -69,6 +69,14 @@ beforeEach(async () => {
       username: "cycle-female",
       email: "cycle-female@example.test",
       gender: "FEMALE",
+      // The suite runs under TZ=UTC and computes its relative day keys with
+      // local Date arithmetic, i.e. in UTC. The route resolves "today" in the
+      // USER's zone and falls back to Europe/Berlin when none is set - one
+      // hour past 22:00 UTC the two clocks disagree about the date and every
+      // day-of-cycle assertion is off by one. Pinning the fixture zone to UTC
+      // makes the test's clock and the route's clock the same clock at any
+      // hour of the day.
+      timezone: "UTC",
     },
   });
   await prisma.user.create({
@@ -77,6 +85,7 @@ beforeEach(async () => {
       username: "cycle-male",
       email: "cycle-male@example.test",
       gender: "MALE",
+      timezone: "UTC",
     },
   });
 });