feat: Implement Statistics API with 8 endpoints under /api/v1/statistics/

- Add statistics.sql with 8 SQL queries for play count statistics
- Generate repository code via sqlc
- Add backend/statistics.go with business logic
- Add server/statistics_handler.go with Echo handlers
- Register protected routes under /api/v1/statistics/ with token auth
- Endpoints: games/most-played, games/least-played, games/never-played,
  games/last-played, games/oldest-played, songs/most-played,
  songs/least-played, summary

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

internal/server/routes.go

@@ -122,10 +122,38 @@ func (s *Server) RegisterRoutes() http.Handler {
 	// Create token auth middleware with pool access
 	tokenAuthMiddleware := middleware.TokenAuthMiddleware(s.db.Pool)
 
-	// Protected group with token authentication - will be used by VGMQ and Statistics API
-	_ = apiV1.Group("", tokenAuthMiddleware)
+	// Protected group with token authentication
+	protectedV1 := apiV1.Group("", tokenAuthMiddleware)
 
-	// Note: Future protected endpoints (VGMQ, Statistics) will be added here
+	// Statistics API endpoints (protected by token auth)
+	statistics := s.statisticsHandler
+	protectedV1.GET("/statistics/games/most-played", func(c *echo.Context) error {
+		return statistics.GetMostPlayedGames(c)
+	})
+	protectedV1.GET("/statistics/games/least-played", func(c *echo.Context) error {
+		return statistics.GetLeastPlayedGames(c)
+	})
+	protectedV1.GET("/statistics/games/never-played", func(c *echo.Context) error {
+		return statistics.GetNeverPlayedGames(c)
+	})
+	protectedV1.GET("/statistics/games/last-played", func(c *echo.Context) error {
+		return statistics.GetLastPlayedGames(c)
+	})
+	protectedV1.GET("/statistics/games/oldest-played", func(c *echo.Context) error {
+		return statistics.GetOldestPlayedGames(c)
+	})
+	protectedV1.GET("/statistics/songs/most-played", func(c *echo.Context) error {
+		return statistics.GetMostPlayedSongs(c)
+	})
+	protectedV1.GET("/statistics/songs/least-played", func(c *echo.Context) error {
+		return statistics.GetLeastPlayedSongs(c)
+	})
+	protectedV1.GET("/statistics/summary", func(c *echo.Context) error {
+		return statistics.GetStatisticsSummary(c)
+	})
+
+	// Future: VGMQ endpoints will be added to protectedV1 group
+	_ = protectedV1 // Use the variable to avoid unused variable error
 
 	routes := e.Router().Routes()
 	sort.Slice(routes, func(i, j int) bool {