Feedback: Hedera Policy Agent - Multi-layer policy enforcement

## Hedera Policy Agent Feedback

### What I built
A multi-layer policy enforcement agent for Hedera payments using the Python Agent Kit.

### Policies implemented
1. **WhitelistPolicy**: Restricts transfers to pre-approved addresses
2. **AmountLimitPolicy**: Blocks transfers exceeding configurable maximums
3. **TimeWindowPolicy**: Restricts transactions to business hours (UTC)
4. **RateLimitPolicy**: Limits transactions per time window
5. **MultiSigPolicy**: Requires multiple approvals for high-value transactions

### Agent Kit experience
- **Ease of use**: 8/10 - Plugin architecture is clean and extensible
- **Documentation**: 7/10 - Good quickstart, but policy/hook docs could be more detailed
- **Issues encountered**:
- AbstractPolicy class import path was not immediately obvious
- No built-in RateLimitPolicy (I had to implement my own)
- Context configuration for hooks/policies requires careful setup

### Suggestions
1. Add built-in RateLimitPolicy to the policy library
2. More examples of custom policy implementations
3. Better error messages when policy configuration is invalid
4. Consider adding a PolicyChain class for composing multiple policies

### Repository
https://github.com/Cloudz-319/hedera-policy-agent

Start by reviewing the existing policy library, AbstractPolicy import path, hook configuration, and related documentation. The issue lists several possible improvements but does not select one or name files or tests; clarify the desired scope and acceptance criteria before beginning.

Written by the indexing model from the issue text.