feat: add ChainSimulatorSetStateStep for chain simulator state patching

[EtienneWallet]

Summary

Add ChainSimulatorSetStateStep to set specific hex-encoded storage key-value pairs for an address on the chain simulator. This enables users to patch storage values after cloning contracts from mainnet when values like round numbers or epoch indices are incompatible with the simulator's timeline.

Changes

• Provider method: Added set_address_state() to MyProxyNetworkProvider to POST hex-encoded key-value pairs to simulator/address/{address}/set-state
• Step implementation: New ChainSimulatorSetStateStep class with:
  • Hex validation for all keys and values
  • Empty dict rejection
  • Network restriction to CHAIN_SIMULATOR
  • Debug logging of simulator response
• Tests: 5 comprehensive test cases covering wrong network, successful execution, empty keys, and invalid hex input
• Documentation: User guide section with YAML schema and example
• Changelog: Updated with feature entry

Testing

• ✅ All 268 unit tests pass
• ✅ Ruff formatting and linting clean
• ✅ Pylint score 9.86/10 (requirement: ≥9.5)
• ✅ Dedicated chain_simulator_scenario fixture for reliable test isolation
• ✅ Edge case coverage: empty keys, invalid hex key/value