…expanded tests

- Add raw-Ethernet fallback when ERSPAN header decode fails (Type I devices
  that send GRE 0x88BE without an ERSPAN header)
- Log ERSPAN decode errors at debug level for easier field diagnostics
- Add SCTP support to decodeInnerPacket and decodeInnerIPPacket
- Add tests: GRE with S-bit, GRE with C+S bits, ERSPAN Type III,
  ERSPAN Type I fallback, inner VLAN-tagged frames

Bump version to 2.0.10.

Ref #336

Add focused GRE/ERSPAN debug logs and a pcap-based ERSPAN Type II regression test so decode failures can be localized quickly in runtime environments.

Replace viper AutomaticEnv with a reflection-based EnvUpdater that covers
all Config fields via HEPLIFY_ prefix, including []TransportSettings,
[]SocketSettings, []ProtocolSettings elements (HEPLIFY_TRANSPORT__0__HOST)
and []string fields inside nested structs (HEPLIFY_SIP_SETTINGS_DISCARD_METHODS__0).

…mples