Foundation for v0.2.0 REST + external WS auth.
Bearer tokens stored as SHA-256 hashes; secrets are 256-bit CSPRNG so
Argon2 would waste cost without security gain.
Adds mesh.api_key table, migration 0023 applied manually to prod, and
helpers: createApiKey, listApiKeys, revokeApiKey, verifyApiKey.
Next slices: CLI apikey verbs and REST endpoints in apps/web router.
Spec: .artifacts/specs/2026-05-02-v0.2.0-scope.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
