fix: sanitize container log output and fix lint issues

- Update nolint comment on log streaming to accurately describe why
  gosec is suppressed (text/plain Content-Type, not HTML)
- Replace <script type="text/plain"> with data attribute for initial
  logs to prevent </script> breakout from attacker-controlled log data
- Move RemoveImage before unexported methods (funcorder)
- Fix file permissions in test (gosec G306)
- Rename unused parameters in export_test.go (revive)
- Add required blank line before assignment (wsl)

internal/handlers/app.go

@@ -499,7 +499,7 @@ func (h *Handlers) HandleAppLogs() http.HandlerFunc {
 			return
 		}
 
-		_, _ = writer.Write([]byte(logs)) //nolint:gosec // logs are from trusted container output, not user input
+		_, _ = writer.Write([]byte(logs)) //nolint:gosec // response Content-Type is text/plain, not rendered as HTML
 	}
 }