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/context.test.ts

@@ -87,7 +87,8 @@ describe("context", () => {
     await a.engine.prompt("read it")
     const system = a.engine.compose(a.engine.mode)
     const text = renderBreakdown(contextBreakdown(a.engine, system, [], undefined, a.engine.o.tools))
-    expect(text).toContain("window 32.8k")
+    expect(text).toContain("/ 32.8k tokens")
+    expect(text).toMatch(/until auto-compact \(at 85%\) — \/compact to compact now/)
     expect(text).toContain("system prompt")
     expect(text).toMatch(/tool definitions \(\d+\)/)
     expect(text).toMatch(/tool results\s+514/) // one 6000-character line, cut at 2000 by read, under its header