feat: add finance module with yearly income/expense tracking

- FinanceEntry model (income/expense x fixed/extra)
- CRUD API endpoints for finance entries
- FinancePage with summary cards and drill-down
- Updated navigation with Finance tab
- Updated todos default filter to active

internal/handler/handler.go

@@ -5,18 +5,20 @@ import (
 	"strconv"
 	"time"
 
+	"lifelog/internal/model"
 	"lifelog/internal/service"
 
 	"github.com/gin-gonic/gin"
 )
 
 type Handler struct {
-	todoSvc     *service.TodoService
-	dailyLogSvc *service.DailyLogService
+	todoSvc      *service.TodoService
+	dailyLogSvc  *service.DailyLogService
+	financeSvc   *service.FinanceService
 }
 
-func NewHandler(todoSvc *service.TodoService, dailyLogSvc *service.DailyLogService) *Handler {
-	return &Handler{todoSvc: todoSvc, dailyLogSvc: dailyLogSvc}
+func NewHandler(todoSvc *service.TodoService, dailyLogSvc *service.DailyLogService, financeSvc *service.FinanceService) *Handler {
+	return &Handler{todoSvc: todoSvc, dailyLogSvc: dailyLogSvc, financeSvc: financeSvc}
 }
 
 // Todo handlers
@@ -165,3 +167,95 @@ func (h *Handler) SaveDailyLog(c *gin.Context) {
 	}
 	c.JSON(http.StatusOK, gin.H{"data": log})
 }
+
+// Finance handlers
+
+func (h *Handler) GetFinanceByYear(c *gin.Context) {
+	yearStr := c.Param("year")
+	year, err := strconv.Atoi(yearStr)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid year"})
+		return
+	}
+	entries, err := h.financeSvc.GetByYear(year)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"data": entries})
+}
+
+func (h *Handler) CreateFinanceEntry(c *gin.Context) {
+	var req struct {
+		Year        int     `json:"year" binding:"required"`
+		Month       int     `json:"month"`
+		Type        string  `json:"type" binding:"required"` // income / expense
+		Category    string  `json:"category" binding:"required"` // fixed / extra
+		Description string  `json:"description"`
+		Amount      float64 `json:"amount" binding:"required"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	entry := &model.FinanceEntry{
+		Year:        req.Year,
+		Month:       req.Month,
+		Type:        req.Type,
+		Category:    req.Category,
+		Description: req.Description,
+		Amount:      req.Amount,
+	}
+	if err := h.financeSvc.Create(entry); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusCreated, gin.H{"data": entry})
+}
+
+func (h *Handler) UpdateFinanceEntry(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
+		return
+	}
+	var req struct {
+		Year        int     `json:"year"`
+		Month       int     `json:"month"`
+		Type        string  `json:"type"`
+		Category    string  `json:"category"`
+		Description string  `json:"description"`
+		Amount      float64 `json:"amount"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	err = h.financeSvc.Update(&model.FinanceEntry{
+		ID:          id,
+		Year:        req.Year,
+		Month:       req.Month,
+		Type:        req.Type,
+		Category:    req.Category,
+		Description: req.Description,
+		Amount:      req.Amount,
+	})
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "updated"})
+}
+
+func (h *Handler) DeleteFinanceEntry(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
+		return
+	}
+	if err := h.financeSvc.Delete(id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "deleted"})
+}