feat: Add Uniswap V4 hook security scanner action

## Summary

Add a `check_v4_hook_safety` action that analyzes Uniswap V4 hook contract addresses to identify permission flags and assess security risks before users interact with hooked pools.

## Motivation

Uniswap V4 hooks can be powerful but dangerous. The `beforeSwapReturnDelta` permission (bit 10) enables a known **NoOp rug pull vector** where a malicious hook can steal user funds by replacing swap logic entirely. Currently, agents have no way to warn users about hook risks before executing swaps.

Hook permissions are encoded in the contract address bits and can be decoded on-chain without needing ABIs or source code.

## Proposed Actions

| Action | Description |
|--------|-------------|
| `check_v4_hook_safety` | Decode hook address permission bits and return a risk assessment |
| `get_pool_hook_info` | For a given token pair, check what hook (if any) is attached and its permissions |

## Permission Flags to Decode

| Bit | Permission | Risk Level |
|-----|------------|------------|
| 6 | beforeSwap | High |
| 7 | afterSwap | Medium |
| 10 | beforeSwapReturnDelta | **CRITICAL** |
| 11 | afterSwapReturnDelta | High |
| 2-5 | Liquidity hooks | Medium |

## Implementation Notes

- Permission bits are encoded in the hook contract address (lowest 14 bits)
- Compare against known allowlisted hooks (Flaunch, Coinbase Verified Pools, etc.)
- Return structured risk score (Low/Medium/High/Critical)
- Could integrate with the existing swap actions to auto-warn before swapping through hooked pools

## References

- [Uniswap V4 Hook Permissions](https://docs.uniswap.org/contracts/v4/concepts/hooks)
- [Allowlisted Production Hooks](https://docs.uniswap.org/contracts/v4/deployments)
- Related to PR #951 (Uniswap V4 action provider)