Examples Smoke broken: npm-single fixture is private, skipped since #482 → "No packages found" #575

Symptom

The Examples Smoke workflow fails on every npm-single-fixture scenario — minimal, label-driven, oidc, prerelease, standing-pr — while monorepo-rust passes. The failing step is releasekit release --dry-run:

[INFO] Running version analysis...
Discovered 1 NPM, 0 Rust, and 0 Dart packages (1 total)
No packages found in workspace
##[error]Process completed with exit code 1.

Root cause

scripts/examples-smoke/build-fixture.ts writes the fixture's root package.json with private: true (since #281, 2026-06-09). #482 (feat(version): skip private npm packages from the release flow by default) then landed, adding a discovery-time skip (versionEngine.ts — if (!this.config.includePrivate)). The npm-single fixture's only package is that private root, and the shipped minimal config sets neither includePrivate nor a version.packages entry naming it — so it's discovered (counted as "1 NPM") and then filtered out → nothing to release → exit 1.

monorepo-rust passes because its member packages (@smoke/js-lib, crates) are public; only the root is private (realistic, and correctly skipped).

Why it went undetected: the Examples Smoke workflow is path-gated to scripts/examples-smoke/**. It last ran green on 2026-06-23; nothing touched those paths through the intervening PRs, so #482's effect on the fixture was invisible until PR #574 (a comments-only cleanup) edited two files there and re-triggered the workflow. #574 does not cause this — reproduced independently on a clean checkout.

Reproduction (local, verified)

Single private package + examples/ci/minimal/releasekit.config.json + one feat: commit past a v1.0.0 tag → releasekit release --dry-run prints "No packages found in workspace", exit 1. Dropping private: true → dry-run reaches [SUCCESS] Publish complete (would publish smoke-consumer@1.1.0).

Fix (verified)

Make the npm-single fixture non-private — a real single publishable package isn't private, and the run is always --dry-run so nothing publishes regardless:

// build-fixture.ts, buildNpmSingle
writeRootPackageJson(out, 'smoke-consumer', { private: false }, tarballNames);

Monorepo fixtures keep their private root (members are public and discovered). The shipped example configs stay untouched — we must NOT add includePrivate: true to examples/ci/**, since real consumers publish public packages.

Secondary (optional)

An all-private workspace surfaces as a terse No packages found in workspace + exit 1. Consider a clearer diagnostic — e.g. "N package(s) discovered but all are private; set version.includePrivate: true to version them" — so a real misconfiguration is self-explaining.