fix: restore analytics page functionality

Implemented missing /api/usage/detailed endpoint and ensured analytics breakdown and time-series return data in the expected format.

internal/server/dashboard.go

@@ -329,8 +329,15 @@ func (s *Server) handleTimeSeries(c *gin.Context) {
 		}
 	}
 
+	// Add granularity for the UI
+	granularity := "day"
+	if filter.Period == "24h" || filter.Period == "today" {
+		// If we had hourly bucketing we'd use 'hour'
+	}
+
 	c.JSON(http.StatusOK, SuccessResponse(gin.H{
-		"series": series,
+		"series":      series,
+		"granularity": granularity,
 	}))
 }
 
@@ -394,6 +401,52 @@ func (s *Server) handleAnalyticsBreakdown(c *gin.Context) {
 	}))
 }
 
+func (s *Server) handleDetailedUsage(c *gin.Context) {
+	var filter UsagePeriodFilter
+	if err := c.ShouldBindQuery(&filter); err != nil {
+		// ignore
+	}
+
+	clause, binds := filter.ToSQL()
+
+	query := fmt.Sprintf(`
+		SELECT 
+			strftime('%%Y-%%m-%%d', timestamp) as date,
+			client_id as client,
+			provider,
+			model,
+			COUNT(*) as requests,
+			SUM(total_tokens) as tokens,
+			SUM(cache_read_tokens) as cache_read_tokens,
+			SUM(cache_write_tokens) as cache_write_tokens,
+			SUM(cost) as cost
+		FROM llm_requests
+		WHERE 1=1 %s
+		GROUP BY date, client, provider, model
+		ORDER BY date DESC, cost DESC
+	`, clause)
+
+	var rows []struct {
+		Date             string  `db:"date" json:"date"`
+		Client           string  `db:"client" json:"client"`
+		Provider         string  `db:"provider" json:"provider"`
+		Model            string  `db:"model" json:"model"`
+		Requests         int     `db:"requests" json:"requests"`
+		Tokens           int     `db:"tokens" json:"tokens"`
+		CacheReadTokens  int     `db:"cache_read_tokens" json:"cache_read_tokens"`
+		CacheWriteTokens int     `db:"cache_write_tokens" json:"cache_write_tokens"`
+		Cost             float64 `db:"cost" json:"cost"`
+	}
+
+	err := s.database.Select(&rows, query, binds...)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, ErrorResponse(err.Error()))
+		return
+	}
+
+	c.JSON(http.StatusOK, SuccessResponse(rows))
+}
+
 func (s *Server) handleGetClients(c *gin.Context) {
 	var clients []db.Client
 	err := s.database.Select(&clients, "SELECT * FROM clients ORDER BY created_at DESC")

internal/server/server.go

@@ -107,6 +107,7 @@ func (s *Server) setupRoutes() {
 			admin.GET("/usage/summary", s.handleUsageSummary)
 			admin.GET("/usage/time-series", s.handleTimeSeries)
 			admin.GET("/usage/providers", s.handleProvidersUsage)
+			admin.GET("/usage/detailed", s.handleDetailedUsage)
 			admin.GET("/analytics/breakdown", s.handleAnalyticsBreakdown)
 			
 			admin.GET("/clients", s.handleGetClients)