fix(desktop): preserve authoritative agent avatars

[tellaho]

Category: fix
User Impact: Agent cards and catalog listings now show the avatar belonging to the identity they represent.

Problem: Running agent cards could show a stale definition avatar instead of the concrete agent profile, while adding another publisher's catalog entry could let local edits repaint that publisher's listing. This made agent identity look inconsistent across My Agents and the Agent Catalog.

Solution: Treat the concrete agent pubkey profile as authoritative for running-card avatars, with the linked definition as fallback. Keep relay publications authoritative for foreign catalog presentation while using local copies only for linkage and selection state.

Changes

File changes

desktop/src/features/agents/lib/agentCardAvatar.ts
Adds the explicit avatar precedence rule for running agent cards and blocks avatar-dependent actions until the authoritative profile query settles.

desktop/src/features/agents/lib/agentCardAvatar.test.mjs
Covers profile precedence, definition fallback, blank avatar handling, and the profile-loading transition for linked-agent actions.

desktop/src/features/agents/lib/personaCatalogRelay.ts
Keeps publisher-provided catalog identity and behavior fields authoritative after a local copy is added.

desktop/src/features/agents/lib/personaCatalogRelay.test.mjs
Verifies local copies contribute linkage and selection without overriding publisher presentation.

desktop/src/features/agents/ui/UnifiedAgentsSection.tsx
Uses the concrete agent profile avatar before the linked definition avatar on running-agent cards.

Reproduction Steps

1. Run an agent whose pubkey profile avatar differs from its linked definition avatar.
2. Open My Agents and verify the running card shows the pubkey profile avatar.
3. Add another publisher's Agent Catalog entry, then rename it and change its avatar locally.
4. Return to the Agent Catalog and verify the publisher's original name, avatar, and instructions remain visible while the entry stays selected.

Validation

• pnpm test — 4,376 passed
• pnpm typecheck — passed
• pnpm check — passed with existing non-error notices