Compatibility test matrix for oh-my-codex/OMX harness integration

[minsing-jin]

Goal

Validate Codexplain against oh-my-codex/OMX-style harnesses without leaking harness state into release commits.

Scope

• Project-local Codexplain activation only by default.
• No .codexplain/state artifacts committed.
• No harness/ or upstream OMX clone content included in release commits unless explicitly intended.

Test Matrix

• codexplain on --project creates only managed local adapter files.
• codexplain off --project removes only Codexplain-managed files/blocks.
• codexplain on --session prints source .codexplain/activate and does not mutate global Codex settings.
• codexplain on --global modifies only the managed CODEXPLAIN block under CODEX_HOME.
• Strict JSON/code/diff/log/test output remains unchanged.
• Width-safe Unicode tables stay within --width and include body row dividers.
• Architecture prompts render boxes/flow before prose.
• Cause-effect prompts render 원인/결과/대응 reports.
• OMX/harness commands do not route outside the current project scope.

Validation Commands

• cargo test
• cargo build --release
• ./bin/codexplain quality-check --width 88
• ./bin/codexplain storage-check --min-free-gb 5