Guard hot-path diagnostics

[Spectralgo]

Summary

• remove per-render Agent CV diagnostics from the normal render path
• remove per-request success diagnostics from the desktop tRPC client and gastown agents list router
• keep error logging for failed tRPC and agents list calls

Validation

• bun test apps/desktop/src/renderer/components/Gastown/AgentCVPanel/AgentCVPanel.test.tsx
• bunx biome check apps/desktop/src/lib/trpc/routers/gastown/agents.ts apps/desktop/src/renderer/components/Gastown/AgentCVPanel/AgentCVPanel.test.tsx apps/desktop/src/renderer/components/Gastown/AgentCVPanel/AgentCVPanel.tsx apps/desktop/src/renderer/lib/trpc-client.ts
• bun run --cwd apps/desktop typecheck

[github-actions]

🧹 Preview Cleanup Complete

The following preview resources have been cleaned up:

• ⚠️ Neon database branch
• ⚠️ Electric Fly.io app

Thank you for your contribution! 🎉