Implement SQLite persistence layer (TDD)

- Add SQLite and UUID dependencies (go-sqlite3, google/uuid)
- Create database connection with automatic migrations
- Implement UserRepository with full CRUD operations
- Implement HabitRepository with JSON serialization for arrays
- Implement HabitEntryRepository with date range queries
- Add comprehensive test coverage for all repositories
- Fix User entity to default timezone to UTC when empty
- All tests passing with TDD approach (Red-Green-Refactor)

internal/infrastructure/persistence/sqlite/migrations_test.go

@@ -0,0 +1,127 @@
+package sqlite
+
+import (
+	"database/sql"
+	"testing"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+func TestRunMigrations(t *testing.T) {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	err = RunMigrations(db)
+
+	if err != nil {
+		t.Fatalf("RunMigrations failed: %v", err)
+	}
+
+	tables := []string{"users", "habits", "habit_entries"}
+	for _, table := range tables {
+		var name string
+		query := "SELECT name FROM sqlite_master WHERE type='table' AND name=?"
+		err := db.QueryRow(query, table).Scan(&name)
+		if err != nil {
+			t.Errorf("Table %s does not exist: %v", table, err)
+		}
+	}
+}
+
+func TestUsersTableSchema(t *testing.T) {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	err = RunMigrations(db)
+	if err != nil {
+		t.Fatalf("RunMigrations failed: %v", err)
+	}
+
+	columns := []string{"id", "email", "password_hash", "timezone", "created_at", "updated_at"}
+	for _, col := range columns {
+		query := "SELECT " + col + " FROM users LIMIT 0"
+		rows, err := db.Query(query)
+		if err != nil {
+			t.Errorf("Column %s does not exist in users table: %v", col, err)
+		}
+		if rows != nil {
+			rows.Close()
+		}
+	}
+}
+
+func TestHabitsTableSchema(t *testing.T) {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	err = RunMigrations(db)
+	if err != nil {
+		t.Fatalf("RunMigrations failed: %v", err)
+	}
+
+	columns := []string{"id", "user_id", "name", "description", "type", "frequency",
+		"specific_days", "specific_dates", "carry_over", "target_value", "created_at", "archived_at"}
+	for _, col := range columns {
+		query := "SELECT " + col + " FROM habits LIMIT 0"
+		rows, err := db.Query(query)
+		if err != nil {
+			t.Errorf("Column %s does not exist in habits table: %v", col, err)
+		}
+		if rows != nil {
+			rows.Close()
+		}
+	}
+}
+
+func TestHabitEntriesTableSchema(t *testing.T) {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	err = RunMigrations(db)
+	if err != nil {
+		t.Fatalf("RunMigrations failed: %v", err)
+	}
+
+	columns := []string{"id", "habit_id", "scheduled_date", "completed_at", "value", "deleted_at"}
+	for _, col := range columns {
+		query := "SELECT " + col + " FROM habit_entries LIMIT 0"
+		rows, err := db.Query(query)
+		if err != nil {
+			t.Errorf("Column %s does not exist in habit_entries table: %v", col, err)
+		}
+		if rows != nil {
+			rows.Close()
+		}
+	}
+}
+
+func TestMigrationsAreIdempotent(t *testing.T) {
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	err = RunMigrations(db)
+	if err != nil {
+		t.Fatalf("First RunMigrations failed: %v", err)
+	}
+
+	err = RunMigrations(db)
+
+	if err != nil {
+		t.Errorf("Second RunMigrations should be idempotent but failed: %v", err)
+	}
+}