Add build log file storage and download functionality

- Write deployment logs to files when deployment finishes (success or failure)
- Log files stored in DataDir/logs/<hostname>/<appname>/<appname>_<sha>_<timestamp>.log.txt
- Capture commit SHA for manual deploys by parsing git rev-parse HEAD after clone
- Add download endpoint for log files at /apps/{id}/deployments/{deploymentID}/download
- Add download link in deployment history view for finished deployments

internal/server/routes.go

@@ -66,6 +66,7 @@ func (s *Server) SetupRoutes() {
 		r.Post("/apps/{id}/deploy", s.handlers.HandleAppDeploy())
 		r.Get("/apps/{id}/deployments", s.handlers.HandleAppDeployments())
 		r.Get("/apps/{id}/deployments/{deploymentID}/logs", s.handlers.HandleDeploymentLogsAPI())
+		r.Get("/apps/{id}/deployments/{deploymentID}/download", s.handlers.HandleDeploymentLogDownload())
 		r.Get("/apps/{id}/logs", s.handlers.HandleAppLogs())
 		r.Get("/apps/{id}/container-logs", s.handlers.HandleContainerLogsAPI())
 		r.Get("/apps/{id}/status", s.handlers.HandleAppStatusAPI())