Write an accepted Codex lifecycle design for autocontext #239

Purpose

Treat autocontext as a separate architecture decision because it has no shared skills and depends on state, commands, an agent, hooks, automatic behavior, and uninstall semantics.

Acceptance criteria

• Inventory commands, agent behavior, hook events, state paths, environment variables, and cleanup.
• Define the Codex user value without mapping components by filename.
• Define lifecycle, persistence, authority, trust, failure, recovery, disable, and uninstall contracts.
• Compare the design against current Codex extension surfaces with versioned evidence.
• Keep autocontext Claude-only until Joe accepts the design.
• If accepted, open bounded implementation issues for each approved adapter surface.
• Add drift and lifecycle tests before any support claim.
• Update the compatibility matrix and public support wording.