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

Move process wiring, technical adapters, and cross-cutting contracts out of flat internal/ packages so new code has a clear home without changing business layout.

internal/infra/task/meta_test.go

@@ -0,0 +1,31 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package task_test
+
+import (
+	"testing"
+
+	"github.com/Rain-kl/Wavelet/internal/infra/task"
+	taskhandlers "github.com/Rain-kl/Wavelet/internal/infra/task/handlers"
+)
+
+func TestDuplicateTaskMeta(t *testing.T) {
+	// Call Register twice to simulate being imported by multiple packages (routers, worker, etc.)
+	taskhandlers.Register()
+	taskhandlers.Register()
+
+	metas := task.GetDispatchableTasks()
+
+	// Check if we have duplicates by checking if a Type appears more than once
+	seen := make(map[string]int)
+	for _, m := range metas {
+		seen[m.Type]++
+	}
+
+	for taskType, count := range seen {
+		if count > 1 {
+			t.Errorf("Task type %q registered %d times, expected at most 1", taskType, count)
+		}
+	}
+}