Remove timezone from User model and pass as request parameter

Timezone is now sent from the client on each request that needs it,
instead of storing it in the database. This simplifies the model and
allows timezone to be dynamic (useful for traveling users).

Changes:
- Remove timezone field from User entity
- Remove timezone from user registration
- GET /habits/today now requires ?timezone= query param
- Add migration to drop timezone column from database
- Update related tests

internal/infrastructure/http/habit_handlers.go

@@ -9,7 +9,6 @@ import (
 
 	"apocapoc-api/internal/application/commands"
 	"apocapoc-api/internal/application/queries"
-	"apocapoc-api/internal/domain/repositories"
 	"apocapoc-api/internal/i18n"
 	"apocapoc-api/internal/shared/errors"
 
@@ -26,7 +25,6 @@ type HabitHandlers struct {
 	archiveHandler         *commands.ArchiveHabitHandler
 	markHandler            *commands.MarkHabitHandler
 	unmarkHandler          *commands.UnmarkHabitHandler
-	userRepo               repositories.UserRepository
 	translator             *i18n.Translator
 }
 
@@ -40,7 +38,6 @@ func NewHabitHandlers(
 	archiveHandler *commands.ArchiveHabitHandler,
 	markHandler *commands.MarkHabitHandler,
 	unmarkHandler *commands.UnmarkHabitHandler,
-	userRepo repositories.UserRepository,
 	translator *i18n.Translator,
 ) *HabitHandlers {
 	return &HabitHandlers{
@@ -53,7 +50,6 @@ func NewHabitHandlers(
 		archiveHandler:         archiveHandler,
 		markHandler:            markHandler,
 		unmarkHandler:          unmarkHandler,
-		userRepo:               userRepo,
 		translator:             translator,
 	}
 }
@@ -440,11 +436,13 @@ func (h *HabitHandlers) GetHabitEntries(w http.ResponseWriter, r *http.Request)
 
 // GetTodaysHabits godoc
 // @Summary Get today's habits
-// @Description Get all habits scheduled for today for the authenticated user. Includes the entry for today if it exists.
+// @Description Get all habits scheduled for today for the authenticated user. Includes the entry for today if it exists. Requires timezone as query parameter (e.g., ?timezone=America/New_York).
 // @Tags habits
 // @Produce json
 // @Security BearerAuth
+// @Param timezone query string true "IANA timezone (e.g., 'America/New_York', 'Europe/Madrid', 'UTC')"
 // @Success 200 {array} TodaysHabitResponse
+// @Failure 400 {object} ErrorResponse "Invalid or missing timezone"
 // @Failure 401 {object} ErrorResponse
 // @Failure 500 {object} ErrorResponse
 // @Router /habits/today [get]
@@ -455,15 +453,16 @@ func (h *HabitHandlers) GetTodaysHabits(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	user, err := h.userRepo.FindByID(r.Context(), userID)
-	if err != nil {
-		respondErrorI18n(w, r, h.translator, http.StatusInternalServerError, "failed_get_user")
+	timezone := r.URL.Query().Get("timezone")
+	if timezone == "" {
+		respondErrorI18n(w, r, h.translator, http.StatusBadRequest, "timezone_required")
 		return
 	}
 
-	loc, err := time.LoadLocation(user.Timezone)
+	loc, err := time.LoadLocation(timezone)
 	if err != nil {
-		loc = time.UTC
+		respondErrorI18n(w, r, h.translator, http.StatusBadRequest, "invalid_timezone")
+		return
 	}
 
 	today := time.Now().In(loc)
@@ -471,7 +470,7 @@ func (h *HabitHandlers) GetTodaysHabits(w http.ResponseWriter, r *http.Request)
 
 	query := queries.GetTodaysHabitsQuery{
 		UserID:   userID,
-		Timezone: user.Timezone,
+		Timezone: timezone,
 		Date:     todayDate,
 	}