fix: support native package verifier scratch

deploy/README.md

@@ -170,9 +170,20 @@ identity, target, and Node.js range against this platform, runs the platform's m
 validation, and loads the backend once in a short-lived process with no environment. Only then does
 it write the verified module directory, to a new directory outside module storage:
 
+The backend probe executes the package's server-side code; the verifier container is its isolation
+boundary. Keep the general-purpose `/tmp` mount `noexec`, and give only this one-shot verifier a
+separate executable scratch tmpfs. The mount below is ephemeral, bounded at 1100 MiB (just above the
+package format's 1 GiB expanded limit), `nodev`, `nosuid`, and writable only by the image's
+unprivileged `node` user. `EKKLESIA_MODULE_VERIFIER_SCRATCH_DIR` tells the CLI where that mount is;
+the verifier creates a unique child for each run and removes it on success or failure.
+
 ```sh
 mkdir -m 777 staging        # writable by the image's unprivileged user; nothing else is
-docker run --rm --network none --read-only --tmpfs /tmp \
+docker run --rm --network none --read-only \
+  --tmpfs /tmp:rw,nosuid,nodev,noexec,size=64m \
+  --tmpfs /run/ekklesia-verifier:rw,nosuid,nodev,exec,size=1100m,mode=0700,uid=1000,gid=1000 \
+  --cap-drop ALL --security-opt no-new-privileges \
+  -e EKKLESIA_MODULE_VERIFIER_SCRATCH_DIR=/run/ekklesia-verifier \
   -v "$PWD:/package:ro" -v "$PWD/staging:/staging" \
   --entrypoint node "$EKKLESIA_IMAGE" core/dist/cli/verify-module-package.js \
   /package/<id>-<version>-any.tar.gz --sha256-file /package/<id>-<version>-any.tar.gz.sha256 \