feat(auth): add MINDA_DEMO support with auto-seeded demo accounts and username login

internal/storage/sqlite.go

@@ -68,6 +68,7 @@ func (s *Store) migrate() error {
 	CREATE TABLE IF NOT EXISTS users (
 		id TEXT PRIMARY KEY,
 		email TEXT UNIQUE NOT NULL,
+		username TEXT NOT NULL DEFAULT '',
 		password_hash TEXT NOT NULL,
 		display_name TEXT NOT NULL,
 		role TEXT NOT NULL DEFAULT 'member',
@@ -267,6 +268,8 @@ func (s *Store) migrate() error {
 
 	// Idempotent column migrations for existing databases
 	columnMigrations := []string{
+		"ALTER TABLE users ADD COLUMN username TEXT NOT NULL DEFAULT '';",
+		"CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);",
 		"ALTER TABLE users ADD COLUMN role TEXT NOT NULL DEFAULT 'member';",
 		"ALTER TABLE users ADD COLUMN is_active INTEGER NOT NULL DEFAULT 1;",
 		"ALTER TABLE users ADD COLUMN alarm_channels TEXT NOT NULL DEFAULT 'discord';",
@@ -291,15 +294,8 @@ func (s *Store) migrate() error {
 		_, _ = s.db.Exec(q)
 	}
 
-	// Remove legacy auto-seeded default user ('admin@mindsift.local') so First-Boot Setup triggers cleanly
-	var legacyUserID string
-	if err := s.db.QueryRow(`SELECT id FROM users WHERE email = 'admin@mindsift.local'`).Scan(&legacyUserID); err == nil && legacyUserID != "" {
-		_, _ = s.db.Exec(`DELETE FROM thoughts WHERE user_id = ?`, legacyUserID)
-		_, _ = s.db.Exec(`DELETE FROM documents WHERE user_id = ?`, legacyUserID)
-		_, _ = s.db.Exec(`DELETE FROM spaces WHERE owner_id = ?`, legacyUserID)
-		_, _ = s.db.Exec(`DELETE FROM task_lists WHERE user_id = ?`, legacyUserID)
-		_, _ = s.db.Exec(`DELETE FROM users WHERE id = ?`, legacyUserID)
-	}
+	// Backfill username for existing accounts where username is empty
+	_, _ = s.db.Exec(`UPDATE users SET username = LOWER(SUBSTR(email, 1, INSTR(email, '@') - 1)) WHERE (username IS NULL OR username = '') AND INSTR(email, '@') > 0`)
 
 	// Default system settings (public registration disabled by default; invite or admin creation required)
 	_, _ = s.db.Exec(`INSERT OR IGNORE INTO system_settings (key, value) VALUES 
@@ -397,7 +393,7 @@ func (s *Store) EnsureDefaultUser() (*domain.User, error) {
 
 // --- USERS ---
 
-const userSelectCols = `id, email, password_hash, display_name, role, is_active, alarm_channels, alarm_email, discord_webhook_url, custom_webhook_url, notify_before_minutes, created_at`
+const userSelectCols = `id, email, username, password_hash, display_name, role, is_active, alarm_channels, alarm_email, discord_webhook_url, custom_webhook_url, notify_before_minutes, created_at`
 
 func parseAlarmChannels(raw string) []string {
 	parts := strings.Split(raw, ",")
@@ -418,7 +414,7 @@ func scanUser(row interface{ Scan(dest ...any) error }) (*domain.User, error) {
 	var isActiveInt int
 	var channelsRaw string
 	err := row.Scan(
-		&u.ID, &u.Email, &u.PasswordHash, &u.DisplayName,
+		&u.ID, &u.Email, &u.Username, &u.PasswordHash, &u.DisplayName,
 		&u.Role, &isActiveInt, &channelsRaw, &u.AlarmEmail,
 		&u.DiscordWebhookURL, &u.CustomWebhookURL, &u.NotifyBeforeMinutes, &u.CreatedAt,
 	)
@@ -443,13 +439,24 @@ func (s *Store) CountUsers() (int, error) {
 }
 
 func (s *Store) CreateUser(email, passwordHash, displayName, role string) (*domain.User, error) {
+	cleanEmail := strings.ToLower(strings.TrimSpace(email))
+	username := strings.Split(cleanEmail, "@")[0]
+	return s.CreateUserWithUsername(cleanEmail, username, passwordHash, displayName, role)
+}
+
+func (s *Store) CreateUserWithUsername(email, username, passwordHash, displayName, role string) (*domain.User, error) {
 	if role != "admin" && role != "team_admin" && role != "member" {
 		role = "member"
 	}
 	cleanEmail := strings.ToLower(strings.TrimSpace(email))
+	cleanUsername := strings.ToLower(strings.TrimSpace(username))
+	if cleanUsername == "" {
+		cleanUsername = strings.Split(cleanEmail, "@")[0]
+	}
 	u := &domain.User{
 		ID:                  domain.NewID("usr"),
 		Email:               cleanEmail,
+		Username:            cleanUsername,
 		PasswordHash:        passwordHash,
 		DisplayName:         strings.TrimSpace(displayName),
 		Role:                role,
@@ -462,9 +469,9 @@ func (s *Store) CreateUser(email, passwordHash, displayName, role string) (*doma
 		CreatedAt:           domain.NowISO(),
 	}
 	_, err := s.db.Exec(
-		`INSERT INTO users (id, email, password_hash, display_name, role, is_active, alarm_channels, alarm_email, discord_webhook_url, custom_webhook_url, notify_before_minutes, created_at)
-		 VALUES (?, ?, ?, ?, ?, 1, '', ?, '', '', 30, ?)`,
-		u.ID, u.Email, u.PasswordHash, u.DisplayName, u.Role, u.AlarmEmail, u.CreatedAt,
+		`INSERT INTO users (id, email, username, password_hash, display_name, role, is_active, alarm_channels, alarm_email, discord_webhook_url, custom_webhook_url, notify_before_minutes, created_at)
+		 VALUES (?, ?, ?, ?, ?, ?, 1, '', ?, '', '', 30, ?)`,
+		u.ID, u.Email, u.Username, u.PasswordHash, u.DisplayName, u.Role, u.AlarmEmail, u.CreatedAt,
 	)
 	if err != nil {
 		return nil, err
@@ -473,13 +480,68 @@ func (s *Store) CreateUser(email, passwordHash, displayName, role string) (*doma
 }
 
 func (s *Store) GetUserByEmail(email string) (*domain.User, error) {
+	return s.GetUserByLogin(email)
+}
+
+func (s *Store) GetUserByLogin(login string) (*domain.User, error) {
+	cleanLogin := strings.ToLower(strings.TrimSpace(login))
+	if cleanLogin == "" {
+		return nil, errors.New("benutzername oder e-mail darf nicht leer sein")
+	}
 	row := s.db.QueryRow(
-		`SELECT `+userSelectCols+` FROM users WHERE email = ?`,
-		strings.ToLower(strings.TrimSpace(email)),
+		`SELECT `+userSelectCols+` FROM users 
+		 WHERE LOWER(email) = ? 
+		    OR (username != '' AND LOWER(username) = ?) 
+		    OR LOWER(display_name) = ?
+		    OR (INSTR(email, '@') > 0 AND LOWER(SUBSTR(email, 1, INSTR(email, '@') - 1)) = ?)
+		 LIMIT 1`,
+		cleanLogin, cleanLogin, cleanLogin, cleanLogin,
 	)
 	return scanUser(row)
 }
 
+// EnsureDemoAccounts seeds admin/admin and user/user accounts for demo evaluation
+func (s *Store) EnsureDemoAccounts() error {
+	s.initMu.Lock()
+	defer s.initMu.Unlock()
+
+	adminHash, err := auth.HashPassword("admin")
+	if err != nil {
+		return err
+	}
+	userHash, err := auth.HashPassword("user")
+	if err != nil {
+		return err
+	}
+
+	// 1. Admin user (admin / admin)
+	adminUser, err := s.GetUserByLogin("admin")
+	if err != nil || adminUser == nil {
+		adminUser, err = s.CreateUserWithUsername("admin@mindsift.local", "admin", adminHash, "Admin", "admin")
+		if err != nil {
+			return fmt.Errorf("failed to create demo admin: %w", err)
+		}
+		_ = s.SeedStarterContent(adminUser)
+	} else {
+		_ = s.UpdateUserPassword(adminUser.ID, adminHash)
+		_, _ = s.db.Exec(`UPDATE users SET is_active = 1, role = 'admin' WHERE id = ?`, adminUser.ID)
+	}
+
+	// 2. Regular user (user / user)
+	normalUser, err := s.GetUserByLogin("user")
+	if err != nil || normalUser == nil {
+		_, err = s.CreateUserWithUsername("user@mindsift.local", "user", userHash, "User", "member")
+		if err != nil {
+			return fmt.Errorf("failed to create demo user: %w", err)
+		}
+	} else {
+		_ = s.UpdateUserPassword(normalUser.ID, userHash)
+		_, _ = s.db.Exec(`UPDATE users SET is_active = 1 WHERE id = ?`, normalUser.ID)
+	}
+
+	return nil
+}
+
 func (s *Store) GetUserByID(id string) (*domain.User, error) {
 	row := s.db.QueryRow(
 		`SELECT `+userSelectCols+` FROM users WHERE id = ?`,