test: add Directory seed smoke

[mj-deving]

Built / tested

Adds a fixture-pinned seed smoke test for the merged DACS Directory scaffold.

The new test loads the shipped data/registrations.example.json ReviewBot seed, serves the real seeded listing anchor bytes from a local fixture, runs the existing indexRegistration() path, and asserts the seed produces one visible active listing with the expected seller, listing id, rails, and stripped [github:...] presentation tag.

This keeps the smoke non-flaky: it proves the starter seed/index path without requiring CI to scan live chain history.

Spec surface

• Community implementation only.
• Exercises the Directory's DACS-1 listing intake / DACS-1 §6.3.6 catalog output path.
• Does not change normative DACS-Standard text or claim chain-inclusion proof beyond the pinned fixture.

Validation

• bun run test:seed
• bun run test — 19/19 passing
• bun run typecheck
• bun run build
• git diff --check
• autoreview --mode local — clean, no accepted/actionable findings

Notes

This follows up on the seed smoke-test starter task suggested in #7 after the seed/signature and reputation-binding fixes landed.