fix(desktop): show cached display names on startup

[TheSentinel454]

Why

Buzz restores cached channels and messages before profile lookups complete. On launch, that briefly exposes pubkey-derived labels in place of familiar display names.

What

• Persist a bounded, relay-scoped cache of last-known display names, NIP-01 names, and NIP-05 handles
• Seed batch profile queries from those labels immediately, while keeping them stale so the existing relay request revalidates them
• Keep cached data presentation-only: avatars and ownership metadata are not persisted or used to seed profile-detail caches
• Remove cleared or missing profiles, purge a relay's labels when its community is removed, and include the cache in local-storage quota recovery
• Add unit coverage for parsing, bounds, eviction, malformed data, and cleared profiles
• Add an E2E regression that delays the relay profile response and verifies the cached name is rendered first

Risk Assessment

Low. The cache is disposable, capped at 1,000 entries per relay, scoped by normalized relay URL, and always revalidated. It contains only public label fields and does not restore avatars, agent ownership, or authorization state.

Verification

• just ci
• pnpm typecheck
• pnpm test — 3,727 passed
• pnpm exec playwright test tests/e2e/channels.spec.ts --grep "cached profile labels" — passed

Generated with Codex

[TheSentinel454]

🤖 Before / after with the relay profile response deliberately delayed:

Before	After