[Adapter] Harden Claude Code compatibility

[teseo]

Kind

fix

Goal

Move the existing Claude Code integration behind the neutral adapter contract without regressing current behavior.

Non-goals

• Adding unrelated Claude Code features.
• Replacing the current wrapper/hook workflow in one migration.
• Changing policy defaults.

Invariants

• Existing install.sh and uninstall.sh workflows remain compatible.
• Existing Claude paths and settings are preserved during migration.
• Existing tests continue to pass.
• Legacy state remains readable until the migration issue is complete.

Behavioral contract / States

Claude Code hooks and wrappers translate into canonical events, receive canonical decisions, and retain current user-facing messages and exit behavior.

Scope surface

install.sh, uninstall.sh, guard/hook.sh, guard/wrapper.bash, guard/wrapper.zsh, and adapter tests.

Acceptance

• Run: bash tests/test.sh and bash tests/test_install.sh.
• Run: python3 -m pytest tests/test_guard.py -v and node --test tests/test_guard.mjs.
• Verify install, session start, blocked tool, allowed tool, and uninstall flows in a temporary home.
• Document compatibility and rollback steps.

Split triggers

• A current behavior is not representable by the neutral contract.
• Migration requires a persisted state format change.

Dependencies / Parent

Blocked by: #1, #2, #3
Parent Epic: #15