fix: hand npm the release artifact's absolute path, so publishing finds it

The first real 0.2.0 publish failed on its first package with ENOENT:
"Publishing ekklesia-contracts-0.2.0.tgz failed: npm error code ENOENT".

The publish workflow passes a relative release path,
--release "$(find package-train …)", which is
package-train/ekklesia-packages-0.2.0. The tool validated the artifacts
relative to the job's working directory, but ran npm in its own
temporary home (cwd /tmp/ekklesia-publish-XXXXXX) with the same relative
path, package-train/ekklesia-packages-0.2.0/ekklesia-contracts-0.2.0.tgz,
which there names nothing. The disposable-registry suite always passed
an absolute path, so it never saw this.

- loadReleaseTrain resolves the release directory once; every artifact
  path is absolute from validation on, and npm is given only that exact
  file's absolute path (anything else is refused at the npm boundary).
- Just before each upload the file is checked against the validated
  bytes once more; the tool logs the absolute path it publishes, and a
  failure names it with npm's path/syscall lines (npm's temporary home
  masked, the token never shown).
- Regression tests: unit tests with a recording npm (relative nested
  release from another cwd; npm's argv, cwd, and the file's existence; a
  changed artifact refused before npm runs), which fail on the previous
  tool; and a disposable-Gitea test that runs the CLI exactly as the
  workflow does, from the Actions artifact layout, round-tripping all
  nine packages byte for byte.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

tests/package-publication.integration.ts

@@ -1,5 +1,5 @@
 import { execFile } from "node:child_process";
-import { mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import { cp, mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import path from "node:path";
 import { promisify } from "node:util";
@@ -28,8 +28,8 @@ const origin = setting("EKKLESIA_TEST_REGISTRY_ORIGIN");
 const releaseDirectory = setting("EKKLESIA_TEST_RELEASE");
 const publishToken = setting("EKKLESIA_TEST_PUBLISH_TOKEN");
 const outsiderToken = setting("EKKLESIA_TEST_OUTSIDER_TOKEN");
-const [mainOwner, burnedOwner, tagOwner] = setting("EKKLESIA_TEST_OWNERS").split(" ");
-if (!origin || !releaseDirectory || !publishToken || !outsiderToken || !tagOwner) {
+const [mainOwner, burnedOwner, tagOwner, layoutOwner] = setting("EKKLESIA_TEST_OWNERS").split(" ");
+if (!origin || !releaseDirectory || !publishToken || !outsiderToken || !layoutOwner) {
   throw new Error("Run this suite with scripts/test-package-publication.sh.");
 }
 const registryOf = (owner: string | undefined) =>
@@ -303,3 +303,57 @@ describe("moving the final tag, interrupted and resumed", () => {
     }
   });
 });
+
+describe("the publish workflow's own invocation", () => {
+  it("publishes from the Actions artifact layout, given a relative release path from another directory", async () => {
+    // Exactly as .github/workflows/publish-packages.yml runs it: the artifact unpacked under
+    // `package-train/` in the job's workspace, and `--release "$(find package-train …)"`.
+    const workspace = await mkdtemp(path.join(tmpdir(), "ekklesia-publish-workspace-"));
+    scratch.push(workspace);
+    const releaseName = path.basename(releaseDirectory);
+    await mkdir(path.join(workspace, "package-train"), { recursive: true });
+    await cp(releaseDirectory, path.join(workspace, "package-train", releaseName), {
+      recursive: true,
+    });
+    const record = path.join(workspace, "publication-record.json");
+    const { stdout } = await execFileAsync(
+      process.execPath,
+      [
+        path.resolve("scripts/publish-package-train.ts"),
+        "--release",
+        `package-train/${releaseName}`,
+        "--registry",
+        registryOf(layoutOwner),
+        "--version",
+        train.manifest.version,
+        "--revision",
+        train.manifest.source.revision,
+        "--manifest-sha256",
+        train.manifestSha256,
+        "--record",
+        record,
+        "--require-public-read",
+        "--allow-http",
+      ],
+      {
+        cwd: workspace,
+        env: { [PUBLISH_TOKEN_VARIABLE]: publishToken, PATH: process.env.PATH ?? "" },
+      },
+    );
+    expect(stdout).toContain(
+      `publishing ${path.join(workspace, "package-train", releaseName, local("@ekklesia/contracts").entry.file)}`,
+    );
+    expect(stdout).not.toContain(publishToken);
+    const published = JSON.parse(await readFile(record, "utf8")) as PublicationRecord;
+    expect(published.packages.map((entry) => entry.outcome)).toEqual(Array(9).fill("published"));
+    for (const name of order) {
+      const version = (await anonymousPackument(layoutOwner, name))?.versions[
+        train.manifest.version
+      ];
+      expect(
+        (await anonymousBytes(version?.dist.tarball ?? "")).equals(local(name).data),
+        name,
+      ).toBe(true);
+    }
+  });
+});