feat(schedule): support KOL subscription targets and random time windows

Extend schedule tasks to dispatch KOL subscription prompts in addition
to prompt rules, add daily/weekly scheduling with fixed or random time
windows, and track dispatch outcomes (last run, status, consecutive
failures).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/scheduler/schedule_dispatch_worker_test.go

@@ -0,0 +1,30 @@
+package scheduler
+
+import "testing"
+
+func TestAggregateDispatchResult(t *testing.T) {
+	tests := []struct {
+		name             string
+		generateCount    int
+		failedCount      int
+		wantStatus       string
+		wantFailureCount bool
+	}{
+		{name: "all success", generateCount: 3, failedCount: 0, wantStatus: "success"},
+		{name: "partial success", generateCount: 3, failedCount: 1, wantStatus: "partial"},
+		{name: "all failed", generateCount: 3, failedCount: 3, wantStatus: "failed", wantFailureCount: true},
+		{name: "zero generate count defaults to one", generateCount: 0, failedCount: 1, wantStatus: "failed", wantFailureCount: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := aggregateDispatchResult(tt.generateCount, tt.failedCount)
+			if got.status != tt.wantStatus {
+				t.Fatalf("status = %q, want %q", got.status, tt.wantStatus)
+			}
+			if got.countAsFailure != tt.wantFailureCount {
+				t.Fatalf("countAsFailure = %v, want %v", got.countAsFailure, tt.wantFailureCount)
+			}
+		})
+	}
+}