fix(hookify): PostToolUse hooks cannot return permissionDecision: deny

[AZERDSQ131]

Problem

In plugins/hookify/core/rule_engine.py, the evaluate_rules function returned permissionDecision: "deny" for both PreToolUse and PostToolUse hook events:

# before
elif hook_event in ['PreToolUse', 'PostToolUse']:
    return {"hookSpecificOutput": {"hookEventName": hook_event, "permissionDecision": "deny"}, ...}

PostToolUse fires after the tool has already executed. The Claude Code hook protocol explicitly states that permissionDecision is only meaningful for PreToolUse. Sending it for PostToolUse produces undefined behaviour (the field is silently ignored or causes a protocol error depending on the runtime version).

Fix

Split the two cases:

• PreToolUse → returns permissionDecision: "deny" as before (correct)
• PostToolUse and all other non-Stop events → returns only systemMessage (the only valid output for post-execution hooks)

Testing

Covered by reading the hook protocol spec and tracing evaluate_rules call sites in pretooluse.py and posttooluse.py.

🤖 Generated with Claude Code

[AZERDSQ131]

Closing: absorbed by #68673 which is a superset covering the same hookify files