Subagents in the CLI (harness spec 3.3.0): the model, capacity, the offer, /context

- A task subagent or a team member runs on the session's model unless the
  person named another in this session's own messages (team/subagents.ts;
  engine.personSaid reads every prompt and mid-turn message, compacted ones
  included). Not named: refused; an agent file's own model is not used.
- Another model on the session's one-model server is refused; a one-request
  session model is not its own subagent, and nothing else is picked.
- The team is offered when a model could serve: the session's with two
  slots, or any usable model off its one-model server; the size note adds
  team_own when the session's model cannot serve its own.
- "Subagents" in /effort, /team, /settings and the config schema; the status
  bar reads "agents 3/4 · 2 subagents working".
- /context: used of the window, one bar by category, each category's share,
  what is free, and "N until auto-compact".
- Conformance runner for the subagents area (26 cases); helper -> task.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/team.test.ts

@@ -94,7 +94,7 @@ describe("a team at work (team.md)", () => {
     expect(t.room.map((m) => ({ from: m.from, to: m.to, report: m.report }))).toEqual([{ from: "parser", to: ["lead"], report: true }])
     expect(t.get("parser")!.state).toBe("finished")
     expect(t.isManager("lead")).toBe(true)
-    expect(teamLabel(t)).toBe("team 2/4")
+    expect(teamLabel(t)).toBe("agents 2/4")
     expect(teamText(app, "")).toContain("- parser — the parser · finished")
     expect(await Bun.file(join(dir, "x.txt")).exists()).toBe(false)
     // A member is not a job to the model.