fix: load complete run log history

[eetoc]

Summary

• Request run logs from offset zero before following live output.
• Scope the log stream to the run's project.
• Make full-history request semantics explicit.
• Include legacy Sandbox history cells in the Run Logs view.
• Render legacy entries alongside V2 runs in chronological order.
• Keep the Run Logs tab available when only legacy history exists.

Root cause

Event details with no V2 Run received historical output through ListSandboxHistory, but the Run Logs view only rendered Event timeline entries. The returned cells[].output was used for conversation data and omitted from the log viewer.

Testing

• AGENT_COMPOSE_BASE=/agent-compose/ npm run check:ui
• Verified the prefixed assets and Event trace API in the deployment environment.
• /usr/local/go/bin/go test -count=1 ./pkg/agentcompose/api ./pkg/runs (backend compatibility verification)