feat: Implement hooks system (PreToolUse, PostToolUse)

[CarGDev]

Summary

Implement a hooks system that allows intercepting tool execution before and after it happens.

Why It's Needed

• Safety: Block dangerous commands before execution
• Backup: Create file backups before modifications
• Security: Prevent credential exposure
• Extensibility: Enable plugins and custom workflows

Hook Types to Implement

PreToolUse

• Fires before any tool executes
• Can block, allow, or modify tool input
• Returns: { decision: "allow" | "deny" | "ask", modifiedInput?, message? }

PostToolUse

• Fires after tool completes
• Can log results, provide feedback, trigger follow-up
• Returns: { feedback?, metadata? }

Configuration Format

{
  "hooks": {
    "PreToolUse": [
      {
        "name": "security-check",
        "matcher": "bash|write|edit",
        "script": ".codetyper/hooks/security.ts"
      }
    ]
  }
}

Acceptance Criteria

• Hook registration and discovery
• PreToolUse hook with allow/deny/ask decisions
• PostToolUse hook with feedback support
• Matcher patterns for tool filtering
• Timeout handling for hooks
• Built-in hook examples

Effort Estimate

3 days

References

• Claude Code: 10 hook types
• OpenCode: 12+ hook types