refactor(structure): group platform, infra, and shared packages

Reorganize internal packages into platform/infra/shared layers and update
imports, docs, and seed-count tests to match current system configs.

internal/infra/task/scheduler/scheduler_test.go

@@ -0,0 +1,42 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package scheduler
+
+import "testing"
+
+func TestWaitForStop(t *testing.T) {
+	tests := []struct {
+		name        string
+		closeDone   bool
+		closeSignal bool
+		wantSignal  bool
+	}{
+		{
+			name:      "explicit stop",
+			closeDone: true,
+		},
+		{
+			name:        "process signal",
+			closeSignal: true,
+			wantSignal:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			done := make(chan struct{})
+			signals := make(chan struct{})
+			if tt.closeDone {
+				close(done)
+			}
+			if tt.closeSignal {
+				close(signals)
+			}
+
+			if got := waitForStop(done, signals); got != tt.wantSignal {
+				t.Errorf("waitForStop() = %t, want %t", got, tt.wantSignal)
+			}
+		})
+	}
+}