feat(directory): clarify service evidence boundaries

[mj-deving]

Submission checklist

• Change stays inside reference-implementations/dacs-directory/
• Existing prototype/conformance wording remains unchanged
• Existing run instructions and license remain unchanged
• No secrets, private endpoints, or non-test keys added

What & why

The Community Directory is a discovery and evidence-reading reference implementation. Its service cards previously placed listing provenance, endpoint declaration, and deal evidence close together without explicitly stating that the Directory had not measured endpoint reachability.

This change gives those facts separate, bounded labels on directory cards and service details:

• listing evidence: fixture, current DACS listing, or legacy SDK listing;
• endpoint declaration: safe HTTPS declaration, absent declaration, or an unsafe declaration that is not shown or linked;
• reachability: always Not measured by Directory in this change;
• identity: the already-derived identity tier;
• deal record: a strict-verified numerator over the total agreement count.

The shared derivation helper keeps the card and detail views consistent. Regression tests cover safe, absent, and unsafe endpoint declarations plus fixture/current/legacy listing states.

This is intentionally complementary to #60. It adds no network probe and does not implement reachabilityHint; it prevents a declared endpoint from being presented as measured availability until that separately scoped work exists. It also makes no service-health, endorsement, reputation-authority, or protocol-conformance claim.

Verification

• bun run test: 152 passed, 0 failed
• bun run typecheck: passed
• bun run build: passed
• Desktop and mobile fixture rendering: no unnamed interactive controls; one service-detail h1; zero mobile horizontal overflow
• Three bounded semantic review rounds: two wording defects corrected, final round clean

Review focus

Please check that the labels remain accurate for current, legacy, fixture, missing-endpoint, and rejected-endpoint records, and that this change stays disjoint from the active reachability-probing design in #60.