implementer.md: agents run host tests only

[Japabu]

The implementer prompt told agents to run cargo test, which is the QEMU harness; CLAUDE.md says agents never run QEMU. The line now says what CLAUDE.md says.

🤖 Generated with Claude Code

[Japabu]

CI on PR #595 ("host" check) is still pending/in-progress, not green.

NOT READY FOR REVIEW

[Japabu]

CI host is green on 090f854 (run 36497522490, conclusion SUCCESS). Pure prose change to an agent brief, no code, no tests to check.

The new line agrees with root CLAUDE.md's Build & test section: cargo test --workspace --exclude toyos-build for host suites, cargo run -- --build-only for the image, agents never run QEMU or a guest test.

Nothing else in implementer.md tells an agent to run a guest test or QEMU: the only other reference is "The T14 is the orchestrator's" (line 33), which explicitly keeps the guest run with the orchestrator.

NOTE: .claude/agents/implementer.md:22 — the new line is 219 characters, unwrapped, while every other paragraph in the file wraps at ~95-99 characters — wrap it to match the file's convention.

Every word in the new line is load-bearing (the two exact commands, the refusal, and the orchestrator hand-off); nothing to REMOVE.

LAND AFTER NAMED CHANGES