Add generate-share-package endpoint for residence sharing

- Add POST /api/residences/:id/generate-share-package/ endpoint
- Add SharePackageResponse DTO with share code and metadata
- Add GenerateSharePackage service method to create one-time share codes
- Update JoinWithCode to deactivate share code after successful use

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/router/router.go

@@ -272,6 +272,7 @@ func setupResidenceRoutes(api *gin.RouterGroup, residenceHandler *handlers.Resid
 		residences.DELETE("/:id/", residenceHandler.DeleteResidence)
 
 		residences.POST("/:id/generate-share-code/", residenceHandler.GenerateShareCode)
+		residences.POST("/:id/generate-share-package/", residenceHandler.GenerateSharePackage)
 		residences.POST("/:id/generate-tasks-report/", residenceHandler.GenerateTasksReport)
 		residences.GET("/:id/users/", residenceHandler.GetResidenceUsers)
 		residences.DELETE("/:id/users/:user_id/", residenceHandler.RemoveResidenceUser)