Add Codex human-gate delivery permissions

[dapi]

What changed

• add restricted and explicit opt-in full-delivery human-gate permission modes
• resolve permissions from CLI, environment, or the safe restricted default with early validation
• generate Codex-compatible global option ordering and surface the effective capability contract
• document authentication, Git/network access, risk, and troubleshooting in help, README files, and the spec
• add deterministic Go coverage plus a separately authorized full-delivery fixture E2E procedure

Why

Issue #37 showed that the old launcher contract could reject current Codex CLI syntax and could not complete normal GitHub delivery under workspace-write. The new semantic mode keeps least privilege by default while allowing explicitly authorized end-to-end delivery.

Impact

Existing users remain on restricted. Users who explicitly select full-delivery run Codex unsandboxed and can commit, push, and create or update a PR when their GitHub authentication and repository permissions allow it. Product, security, production, and destructive decisions still require STATUS: HUMAN_GATE.

Validation

• make test
• bash -n test/e2e/human-gate.sh
• shellcheck test/e2e/human-gate.sh
• Codex CLI 0.145.0 parser/help validation for both generated command forms

Manual evidence gate

The live full-delivery fixture scenario was not run because repository policy requires a separate explicit request for live agent E2E. It is guarded by both START_ISSUE_E2E=1 and START_ISSUE_E2E_FULL_DELIVERY=1.

Closes#37