Build project-local harness on explicit skill invocation

[revfactory]

Change

Explicit $harness / $codex-harness:harness invocation now directs Codex to build or update a durable harness in the target project before an accompanying ordinary content task. An explicit read-only or audit request still limits writes.

The skill requires every generated agent definition under <target>/.codex/agents/ and keeps skills, AGENTS.md pointers, run state, and communication records in the target. It checks the parent session's cwd before native project-work spawning, since spawn_agent cannot select a child cwd. If protected project paths reject writes, it reports the exact error and leaves bootstrap incomplete instead of relocating definitions or changing permissions. The bootstrap flow also handles plugin-only installation without assuming the checkout's root installer exists.

Updated English, Korean, and Japanese usage guides, quickstart, compatibility notes, trigger examples, and changelog.

Verification

• python3 scripts/validate.py --project . — fails on five pre-existing ignored .harness/runs/* records whose project_root points to /Users/robin/Downloads/codex-harness. A clean copy of the 88 tracked files passes structural validation: 5 agents, 1 skill, 0 errors.
• python3 -m unittest discover -s tests -v — 94 tests passed.
• git diff --check — passed.
• Live Codex smoke test — CLI 0.155.0 with gpt-6-sol, started in a fresh temporary target with inherited model/permission preferences. An ordinary writing request invoking $harness created article.md, AGENTS.md, two project-local agent TOMLs, an orchestrator skill, and completed write/review run records. Target structural and run completion validation passed; codex exec exited 0. Parent and both child session metadata had the target cwd and gpt-6-sol model. Newly written custom roles were not loaded into that active session, so the actual children used built-in worker/explorer roles with the project-local instructions. A plugin-only fresh-target bundle copy was not separately exercised in this smoke test.

Compatibility

• User-visible changes documented in CHANGELOG.md and usage guides.

The optional installer still supplies the predefined five-agent scaffold. Existing project content, inherited model, and permission settings remain under the user's control. Agent definition location and native child execution are tracked separately.