- Add FaultStatus struct with all fault flags as named bool fields
- Add helper methods: has_overcurrent(), has_thermal(), has_voltage_fault(),
  is_ok(), and per-phase overcurrent helpers
- Update get_fault_status() to return FaultStatus instead of tuple
- Remove redundant get_overcurrent_status() (info now in FaultStatus)
- Add FaultStatus usage examples to README and example files
- Bump version to 0.2.0