SubagentsPi container validation #1 (pre-strengthening) — fix-git PASS, zero delegation

First-ever container run of harnesses.subagents_pi:SubagentsPi (single task, FAST_TIMEOUTS=off). Purpose: exercise the container-only pieces of the subagents harness — and it did:

• pi install npm:pi-subagents@0.33.1 marker present in trial.log ("pi-subagents package installed (subagent tool available)").
• Provider extension written to $HOME/.pi/agent/extensions/pi-llama-local.ts (global auto-discovery path; no parent --extension flag).
• All five extension markers in pi.txt, including "subagent workflow prompt active".
• rm -rf .pi-subagents cleanup appended to the run command.
• fix-git PASS, 1m04s wall / 25s agent.

Key finding: 48 bash calls, ZERO subagent calls. The original advisory workflow phrasing ("Work through these stages in order") did not make qwen3.6-35b-a3b delegate at all — reproduced on the host with the tool proven available, so this is prompt strength, not tool availability. An A/B against plain pi with this phrasing would have measured nothing. Fixed the same evening by making STAGE 1 the mandatory first action ("make your very FIRST action a subagent tool call with agent scout"); see the rerun fast__qwen3.6-35b-a3b__20260706-230157.