docs(names): specify portable identity disambiguation

[loganj]

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Summary

Other Buzz clients need a precise way to reproduce the desktop app’s duplicate-name labels. This extracts the existing behavior into a client-independent specification and supplies shared input/output examples that clients can use to check their implementations. It does not change runtime behavior.

Details

• Defines human-first, mine-before-others priority; comparison contexts; multiple aliases for one identity; exact text normalization; owner qualifiers; and repeated collision checks through full-key fallback counters.
• Separates display names from identity and authorization, and the shared naming algorithm from desktop-specific fact selection.
• Adds 31 portable JSON cases and runs them through the desktop app’s production resolver in its existing test suite. All 14 original policy tests remain unchanged, including ordering and alias checks; integration tests are untouched.
• Links the spec from the README. Uses the feature-contract style in this repo and the normative rules/shared-fixture approach in block/buzz’s NIP-MP specification. No new event format or NIP is introduced.

Validation

All 46 policy tests pass. Pre-push checks passed TypeScript, 47 selected tests, and design checks at 8b10641. Local links in the specification were checked. No browser or native build was needed for this documentation and test-only change.

[loganj]

🤖 Validation at 8b10641: all applicable hosted checks now pass; Windows native validation was skipped as configured. The first run failed two assertions in the unchanged new-message browser journey (Chromium: second sent message visibility; WebKit: transient removal image). Both failed jobs passed on one rerun without code changes. The same runtime/browser sources also passed on base main 82bb3a6 (run 36029796120). This records intermittent browser failures; the retry is not a fix for them. Spec and fixture changes remain runtime-neutral.