Add data export functionality with gzip compression

- Add FindByUserID method to HabitEntryRepository (JOIN with habits)
- Implement ExportUserDataHandler to export all user data
- Add GET /api/v1/export endpoint with gzip compression
- Apply strict rate limiting (1 export per hour per user)
- Export includes all habits (active + archived) and entries
- Add i18n translations for export errors (en/es)
- Update all test mocks to implement new repository method
- Export format: JSON with gzip (~10x compression ratio)

internal/infrastructure/http/router.go

@@ -16,7 +16,7 @@ import (
 	_ "apocapoc-api/docs"
 )
 
-func NewRouter(appURL string, habitHandlers *HabitHandlers, authHandlers *AuthHandlers, statsHandlers *StatsHandlers, healthHandlers *HealthHandlers, userHandlers *UserHandlers, jwtService *auth.JWTService, translator *i18n.Translator) *chi.Mux {
+func NewRouter(appURL string, habitHandlers *HabitHandlers, authHandlers *AuthHandlers, statsHandlers *StatsHandlers, healthHandlers *HealthHandlers, userHandlers *UserHandlers, exportHandlers *ExportHandlers, jwtService *auth.JWTService, translator *i18n.Translator) *chi.Mux {
 	r := chi.NewRouter()
 
 	r.Use(middleware.Logger)
@@ -77,5 +77,11 @@ func NewRouter(appURL string, habitHandlers *HabitHandlers, authHandlers *AuthHa
 		r.Delete("/me", userHandlers.DeleteAccount)
 	})
 
+	r.Route("/api/v1/export", func(r chi.Router) {
+		r.Use(AuthMiddleware(jwtService))
+		r.Use(RateLimitByUser(jwtService, 1, 1*time.Hour))
+		r.Get("/", exportHandlers.ExportData)
+	})
+
 	return r
 }