feat: add core data model

backend/internal/domain/models_test.go

@@ -0,0 +1,23 @@
+package domain
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/glebarez/sqlite"
+	"gorm.io/gorm"
+)
+
+func TestAutoMigrateCreatesCoreTables(t *testing.T) {
+	database, err := gorm.Open(sqlite.Open("file::memory:?cache=shared"), &gorm.Config{})
+	require.NoError(t, err)
+
+	require.NoError(t, AutoMigrate(database))
+
+	for _, table := range []string{
+		"users", "projects", "inbox_items", "tasks", "notes", "sources",
+		"ai_sessions", "tags", "project_events", "ai_keys", "ai_call_logs", "task_shares",
+	} {
+		require.True(t, database.Migrator().HasTable(table), "missing table %s", table)
+	}
+}