Read the plan service's today from the scheduler's clock

The plan service read "today" from time.Now, so the plan-draft schedule
tests could not pin the plan_ready title on the fake clock. NewService now
takes a clock; the server passes the scheduler's Now. The plan-draft tests
read the started scheduler's fake clock and assert each plan_ready row's
title and channel alongside the existing key assertions.

Maestro task ece60217-04d0-43a4-9690-4aba2a00d420

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/plan/plan_test.go

@@ -146,7 +146,7 @@ func newEnv(t *testing.T) *env {
 	if err != nil {
 		t.Fatal(err)
 	}
-	e.svc, err = plan.NewService(st, drafter, e.runner, e.gcal, notifytest.New(t, st), func() {}, publicURL, logger)
+	e.svc, err = plan.NewService(st, drafter, e.runner, e.gcal, notifytest.New(t, st), func() {}, publicURL, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}