fix: reminder_time format for habits and tasks (HH:MM instead of timestamp)

internal/model/task.go

@@ -2,6 +2,7 @@ package model
 
 import (
 	"database/sql"
+	"strings"
 	"time"
 )
 
@@ -14,7 +15,7 @@ type Task struct {
 	Color           string         `db:"color" json:"color"`
 	DueDate         sql.NullTime   `db:"due_date" json:"-"`
 	DueDateStr      *string        `db:"-" json:"due_date"`
-	Priority        int            `db:"priority" json:"priority"` // 0=none, 1=low, 2=medium, 3=high
+	Priority        int            `db:"priority" json:"priority"`
 	ReminderTime    sql.NullString `db:"reminder_time" json:"-"`
 	ReminderTimeStr *string        `db:"-" json:"reminder_time"`
 	CompletedAt     sql.NullTime   `db:"completed_at" json:"-"`
@@ -28,8 +29,22 @@ func (t *Task) ProcessForJSON() {
 		s := t.DueDate.Time.Format("2006-01-02")
 		t.DueDateStr = &s
 	}
-	if t.ReminderTime.Valid {
-		t.ReminderTimeStr = &t.ReminderTime.String
+	if t.ReminderTime.Valid && t.ReminderTime.String != "" {
+		timeStr := t.ReminderTime.String
+		// Handle formats like "0000-01-01T19:00:00Z" or "19:00:00"
+		if strings.Contains(timeStr, "T") {
+			parsed, err := time.Parse(time.RFC3339, timeStr)
+			if err == nil {
+				formatted := parsed.Format("15:04")
+				t.ReminderTimeStr = &formatted
+				return
+			}
+		}
+		// Handle "19:00:00" format
+		if len(timeStr) >= 5 {
+			formatted := timeStr[:5]
+			t.ReminderTimeStr = &formatted
+		}
 	}
 	t.Completed = t.CompletedAt.Valid
 }
@@ -39,9 +54,9 @@ type CreateTaskRequest struct {
 	Description  string  `json:"description,omitempty"`
 	Icon         string  `json:"icon,omitempty"`
 	Color        string  `json:"color,omitempty"`
-	DueDate      *string `json:"due_date,omitempty"` // YYYY-MM-DD
+	DueDate      *string `json:"due_date,omitempty"`
 	Priority     int     `json:"priority,omitempty"`
-	ReminderTime *string `json:"reminder_time,omitempty"` // HH:MM
+	ReminderTime *string `json:"reminder_time,omitempty"`
 }
 
 type UpdateTaskRequest struct {