Add local-business storefront catalog example (SMB as an agentic resource)

[jrajaratnam]

What

Adds conformance/examples/local-business/local-business-catalog.json — a worked
ai-catalog.json for a fictional small local business (a plumbing company at the
RFC 2606 domain bobs-plumbing.example), following the pattern established by the
FDA Drug NDC Directory example (#46).

Why a local-business example

The existing examples cover an enterprise API (FDA, #46) and generic/basic
catalogs. The long tail of agentic resources is neither: it's the millions of
small businesses whose "agent surface" is a conversational assistant plus a
handful of storefront tools (availability, quotes, hours). This example shows
what publishing that surface looks like end to end:

• One business, two artifact types — an application/a2a-agent-card+json
  entry (conversational agent, referenced via url at the registered
  /.well-known/agent-card.json path) and an application/mcp-server-card+json
  entry (structured storefront tools, embedded via data) — exercising both
  halves of strict value-or-reference (§3.4).
• SMB-grade trust — a trustManifest whose attestations are the local
  equivalents of enterprise compliance: a state contractor license lookup and a
  liability-insurance certificate (attestation type treated as an open set,
  as in Add FDA Drug NDC Directory API catalog example #46).
• Schema.org-vocabulary metadata (§4.5) — schemaOrgType, address,
  telephone, service area, opening hours — the filter dimensions a registry
  needs for "find me a plumber open now near Minneapolis"-class queries.
• RFC 2606 naming — bobs-plumbing.example per ADR-0003.

Conformance

Passes conformance/bin/conformance-test manifest with strict JSON Schema
validation enabled (0 errors, 0 warnings): URN format, value-or-reference, and
representativeQueries sizing all green.

Note on type + mediaType

Each entry emits the IANA media type under both type and mediaType,
with identical values. The base ai-catalog spec and this spec's examples have
not fully converged on one property name (see #43 and #27, both of which emit
the pair for cross-spec compatibility). The schema tolerates the extra
property, and publishers like us are already dual-emitting in production so
consumers of either spelling can parse the catalogs. Happy to collapse this
example to a single field the moment the WG settles the canonical name — which
would be great to see happen before the 1.0 media-type freeze.

[jrajaratnam]

Cross-referencing the two open issues this example touches:

• Recognise application/install-manifest+json in the AI Catalog (install-time safety envelope) #43 (install-manifest media type) and Recognise OKF bundles in the AI Catalog (a blessed application/okf-bundle media type) #27 (OKF bundle media type) both note the
  type vs mediaType naming split and both propose emitting the pair until the
  canonical field is settled. This example does the same, deliberately, so it can
  serve as a conformance fixture for either resolution.
• If the maintainers prefer examples to stay single-field (as the FDA example in
  Add FDA Drug NDC Directory API catalog example #46 does), say the word and I'll drop mediaType here — but it would be good to
  get the canonical spelling locked before the 1.0 media-type freeze / AAIF joint
  submission window, since publishers are already shipping catalogs against v0.9.