Add local npm registry publish and install (#139)

In-house npm packages have nowhere to publish: npm locals only accept raw file uploads, which `npm publish` and `npm install` cannot use.

- accept `npm publish` (`PUT /api/v1/local/<repo>/<pkg>`, scoped included) on local npm repos, capping the body at 256MiB and verifying the tarball against dist integrity
- write tarball, then manifest, then dist-tags; publishing an existing version returns 409 and leaves tags alone, while a matching leftover tarball from a failed publish is reused so retries complete
- serve packuments with tarball URLs pointing back at the local repo, dropping dist-tags that name unpublished versions
- document the `.npmrc` registry + `_authToken` setup in the UI and `docs/npm/local.md`
- add a stock `node:22` publish/install e2e-docker case

Reviewed-on: #139
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

e2e-docker/README.md

@@ -27,7 +27,9 @@ already-running stack.
   verified against the origin fixture.
 - **Local uploads** — puppet (Forge v3 API via real `r10k` and `puppet module install`),
   generic (upload/download), pypi (wheel + generated `simple/`
-  index), rpm (real package + **automatic repodata** generation).
+  index), rpm (real package + **automatic repodata** generation), npm (stock
+  `node:22` client: `npm publish` unscoped + scoped, `npm install` + `require()`,
+  second version, republish rejected).
 - **Virtual repositories** — pypi simple-index merge and helm `index.yaml` merge
   across two members.
 - **Mirrorlist** — an rpm remote with a `mirrorlist` of extra upstream mirrors

e2e-docker/npm_local_test.go

@@ -0,0 +1,62 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+)
+
+// TestLocalNPMPublishInstall drives a stock npm client against a local npm
+// repo: publish unscoped and scoped packages, install and require() them in a
+// fresh project, publish a second version, and reject a republish.
+func TestLocalNPMPublishInstall(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := os.Getenv("ARTIFACTAPI_INTERNAL")
+	if network == "" || internal == "" {
+		t.Skip("COMPOSE_NETWORK/ARTIFACTAPI_INTERNAL not set; run via scripts/docker-e2e.sh")
+	}
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skip("docker not available on the test host")
+	}
+
+	name := fmt.Sprintf("e2e-npm-local-%d", time.Now().UnixNano())
+	createRepo(t, fmt.Sprintf(`{"name":%q,"package_type":"npm","repo_type":"local"}`, name))
+	defer deleteRepo(t, name)
+
+	reg := strings.TrimRight(internal, "/") + "/api/v1/local/" + name + "/"
+	script := `set -euo pipefail
+printf 'registry=%s\n%s:_authToken=unused\n' "$REG" "${REG#http:}" > ~/.npmrc
+mk() { d="/w/src/$1-$2"; mkdir -p "$d"; cd "$d"
+  printf '{"name":"%s","version":"%s","main":"index.js"}' "$1" "$2" > package.json
+  echo "module.exports = '$1@$2';" > index.js; }
+mk e2e-npm-plain 1.0.0 && npm publish
+mk @e2e/npm-scoped 1.0.0 && npm publish
+mk e2e-npm-plain 1.0.0
+if npm publish 2>/dev/null; then echo "republish accepted"; exit 1; fi
+mkdir -p /w/app && cd /w/app && npm init -y >/dev/null
+npm install --no-audit --cache /tmp/fresh-cache e2e-npm-plain @e2e/npm-scoped
+node -e "console.log('REQ', require('e2e-npm-plain'), require('@e2e/npm-scoped'))"
+mk e2e-npm-plain 1.1.0 && npm publish
+echo "VERSIONS $(npm view e2e-npm-plain versions --json | tr -d ' \n')"
+echo "LATEST $(npm view e2e-npm-plain dist-tags.latest)"`
+
+	out, err := exec.Command("docker", "run", "--rm", "--network", network,
+		"-e", "REG="+reg, "node:22", "bash", "-c", script).CombinedOutput()
+	if err != nil {
+		t.Fatalf("npm client run failed: %v\n%s", err, out)
+	}
+	for _, want := range []string{
+		"REQ e2e-npm-plain@1.0.0 @e2e/npm-scoped@1.0.0",
+		`VERSIONS ["1.0.0","1.1.0"]`,
+		"LATEST 1.1.0",
+	} {
+		if !strings.Contains(string(out), want) {
+			t.Fatalf("missing %q in npm output:\n%s", want, out)
+		}
+	}
+}