[hookify] Add "ask" action type to prompt user for approval (maps to permissionDecision: "ask")

Feature request

The hookify plugin currently supports two action types:

• warn — shows message, allows operation
• block — hard deny, no override possible

Claude Code's native hook system supports a third permissionDecision value: "ask", which prompts the user to approve or deny the specific operation. Hookify should expose this as action: ask (or action: confirm).

Use case

I have a hookify rule that guards systemctl enable/disable/stop/start commands. These should require my explicit approval per-command, but:

• warn is too weak — the model can reason past it
• block is too strong — I can't approve legitimate operations without editing the rule file or running the command manually with !

What I need is: show me a prompt, I click approve or deny. That's exactly what permissionDecision: "ask" does natively.

Proposed change

In the hookify rule engine (core/rule_engine.py), when a matching rule has action: ask, return:

{
  "hookSpecificOutput": {
    "hookEventName": "PreToolUse",
    "permissionDecision": "ask"
  },
  "systemMessage": "<rule message>"
}

Rule file example

---
name: confirm-systemctl
enabled: true
event: bash
pattern: systemctl\s+(enable|disable|stop|start)\s+
action: ask
---

You are changing a systemd service state. Confirm this is approved.

Why this matters

The warn action relies on the model's self-discipline to follow the warning message. As documented in issue #46991, the model can reason past warnings by deciding conversation context implies approval. The ask action would put the decision in the user's hands via a native Claude Code permission prompt, which the model cannot bypass.