fix: resolve go vet error and dayStart logic in ComputeDailyTotals

- Fix 'string(d)' int-to-rune conversion in rpg_test.go by using fmt.Sprintf
- Fix ComputeDailyTotals dayStart logic: initial state should be StateWorking
  when dayStart > 0, correctly counting work from dayStart to first out event
- Update README project structure to reflect new domain/handler/repo layout
- Implement missing achievements: rpg_pioneer (on RPG enable) and
  salary_setter (on first rate set)
- Add tryUnlockAchievement helper to Handler

internal/repo/interface.go

@@ -0,0 +1,59 @@
+package repo
+
+import "worktimeBot/internal/domain"
+
+type Repository interface {
+	// Users
+	GetOrCreateUser(chatID int64) (*domain.User, error)
+	UpdateUser(user *domain.User) error
+	GetAllUsers() ([]domain.User, error)
+
+	// Settings
+	GetOrCreateSettings(userID int64) (*domain.UserSettings, error)
+	UpdateSettings(st *domain.UserSettings) error
+	MarkReportSent(userID int64, date string) error
+
+	// Days
+	GetOrCreateDay(userID int64, date string) (*domain.Day, error)
+	GetDay(userID int64, date string) (*domain.Day, error)
+	UpdateDay(day *domain.Day) error
+	GetUserDaysInRange(userID int64, start, end string) ([]domain.Day, error)
+	SetDayOff(userID int64, date, reason string) error
+	RemoveDayOff(userID int64, date string) error
+
+	// Events
+	CreateEvent(userID, dayID int64, eventType string, workTypeID *int64, occurredAt int64, note string) error
+	GetLastEvent(userID int64) (*domain.Event, error)
+	EventsForDayByDate(userID int64, date string) ([]domain.Event, error)
+	EventsForDayByDayID(dayID int64) ([]domain.Event, error)
+	GetEventByID(eventID, userID int64) (*domain.Event, error)
+	UpdateEventTime(eventID int64, occurredAt int64) error
+	UpdateEventWorkType(eventID, workTypeID int64) error
+	SetEventNote(eventID int64, note string) error
+	DeleteEvent(eventID int64) error
+	GetDistinctEventDates(userID int64, start, end string) ([]string, error)
+	GetDatesWithEvents(userID int64) ([]string, error)
+
+	// Work Types
+	GetWorkTypes() ([]domain.WorkType, error)
+	GetWorkType(id int64) (*domain.WorkType, error)
+
+	// RPG
+	GetOrCreateRPGStats(userID int64) (*domain.RPGStats, error)
+	UpdateRPGStats(stats *domain.RPGStats) error
+	UpsertDailyXP(userID int64, date string, xpEarned, workSeconds int64) error
+	SetDailyWorkSeconds(userID int64, date string, workSeconds int64) error
+	SumDailyWorkSeconds(userID int64) (int64, error)
+
+	// Achievements
+	GetAchievementByCode(code string) (*domain.Achievement, error)
+	UnlockAchievement(userID, achievementID int64) (bool, error)
+	HasAchievement(userID int64, code string) (bool, error)
+	GetUserAchievements(userID int64) ([]domain.UserAchievement, error)
+
+	// League
+	GetLeagueRankings(orderBy string) ([]domain.LeagueEntry, error)
+
+	// Lifecycle
+	Close() error
+}