feat: implement live-sync for tasks, workspace note sharing, and document locking system

internal/storage/sqlite_test.go

@@ -108,4 +108,57 @@ func TestStoreLifecycle(t *testing.T) {
 	if err != nil {
 		t.Fatalf("UpdateSystemSettings failed: %v", err)
 	}
+
+	// 8. Test Document Sharing & Permissions
+	user2, err := store.CreateUser("collab@example.com", "hash", "Collab User", "member")
+	if err != nil {
+		t.Fatalf("CreateUser collab failed: %v", err)
+	}
+	newDoc, err := store.CreateDocument(user.ID, "", "Test Note", "📄", "", []domain.DocumentBlock{
+		{ID: "blk_1", Type: "bullet", Content: "Geheim", Level: 0},
+	}, []string{"test"}, false)
+	if err != nil {
+		t.Fatalf("CreateDocument failed: %v", err)
+	}
+
+	// Share with user2 as "read"
+	share, err := store.CreateDocShare(user.ID, newDoc.ID, user2.ID, "read")
+	if err != nil || share.Permission != "read" {
+		t.Fatalf("CreateDocShare failed: %v", err)
+	}
+
+	// user2 can get document
+	docForUser2, err := store.GetDocumentByID(user2.ID, newDoc.ID)
+	if err != nil || docForUser2.Permission != "read" || docForUser2.IsOwner {
+		t.Fatalf("GetDocumentByID for user2 failed or wrong permission: %v", err)
+	}
+
+	// user2 tries to edit read-only doc -> must fail
+	updatedTitle := "Hacked Title"
+	_, err = store.UpdateDocument(user2.ID, newDoc.ID, &updatedTitle, nil, nil, nil, nil, nil)
+	if err == nil {
+		t.Fatalf("expected UpdateDocument to fail for read-only user, but succeeded")
+	}
+
+	// Upgrade to write permission
+	_, err = store.CreateDocShare(user.ID, newDoc.ID, user2.ID, "write")
+	if err != nil {
+		t.Fatalf("Upgrade CreateDocShare failed: %v", err)
+	}
+
+	// user2 edits writeable doc -> must succeed
+	_, err = store.UpdateDocument(user2.ID, newDoc.ID, &updatedTitle, nil, nil, nil, nil, nil)
+	if err != nil {
+		t.Fatalf("UpdateDocument failed for write collaborator: %v", err)
+	}
+
+	// Remove share
+	err = store.DeleteDocShare(user.ID, newDoc.ID, user2.ID)
+	if err != nil {
+		t.Fatalf("DeleteDocShare failed: %v", err)
+	}
+	_, err = store.GetDocumentByID(user2.ID, newDoc.ID)
+	if err == nil {
+		t.Fatalf("expected GetDocumentByID to fail after share removed, but succeeded")
+	}
 }