feat: add relay-local reputation provider

[branarakic-agent]

Summary

• add an explicit disabled | local | dkg reputation-provider selection while preserving existing DKG-trust deployments by default
• resolve channel-scoped NIP-32 vouches plus the authenticated viewer's exact public NIP-85 30382:<result> selections from the tenant-scoped relay store
• return normalized buzz-trust-claim@1 evidence with original signed events, lifecycle state, pagination, source diagnostics, and honest complete/partial/unavailable semantics
• advertise a backend-neutral buzz-reputation@1 capability and let the desktop show a standalone community-trust surface without requiring DKG memory
• avoid false projection failures on relay-only providers; DKG-enabled communities retain the graph-projection path

Safety and bounds

• canonical relay membership and channel-read authorization still run before provider resolution
• host-derived community and server-resolved channel scopes are never client-selectable
• local reads have a 2-second deadline, 100-claim page cap, 500-event source window, and 32-source NIP-85 cap
• external NIP-85 relay hints are never fetched server-side; unresolved/private/truncated sources produce partial
• supersession is accepted only for an existing same-issuer/same-subject replacement
• disabled, complete, partial, and unavailable providers share one conformance harness

Verification

• cargo test -p buzz-relay --lib --locked (937 tests; DB/Redis integration cases remain ignored by their existing gates)
• cargo clippy -p buzz-relay --lib --locked -- -D warnings
• pnpm --dir desktop test
• pnpm --dir desktop typecheck
• focused Biome check for the changed desktop files
• cargo fmt --all -- --check
• git diff --check

Stack

Stacked on #4 (feat/reputation-provider-foundation). Only the two M2 commits appear in this PR.

[branarakic-agent]

Review pass completed at adbac26. Two blockers remain in the local-provider delta. First, relayProjectsTrustToDkg checks only the generic memory capability; a relay that advertises memory but not dkg-trust@1 will receive unsupported trust projections that are then retained and retried indefinitely. Require both memory and trust support, while keeping the event-only local-provider path. Second, the local provider returns up to 100 claims with the complete raw Nostr event embedded in every sourceDocument, but this response bypasses the bounded-response path used by the DKG adapter. Valid large events can therefore produce multi-megabyte trust responses and defeat the new bounded-query contract. Cap or omit raw source payloads and enforce a response byte ceiling, with tests near the limit. The branch CI is also currently red.