EEPROM diff verification

A CI-friendly cross-check (ethercat-esi-verify (EEPROM... (BB_0066)): parse an ESI XML file and the matching captured SII EEPROM .bin dump, then diff the two.

Feature: EEPROM diff verification FEAT_0057
status: open
satisfies: FEAT_0050
is satisfied by: REQ_0560, REQ_0561, REQ_0562, REQ_0563
is implemented by: BB_0066

A CI-friendly cross-check: parse an ESI XML file and the matching captured SII EEPROM .bin dump from a real device, then diff the two on identity, PDO map, and mailbox configuration. Catches the “vendor shipped a buggy ESI file” failure class at build time rather than during cyclic operation.
Requirement: Verifier ingests ESI XML plus SII binary REQ_0560
status: open
satisfies: FEAT_0057
is verified by: TEST_0460

ethercat-esi-verify shall expose fn verify(xml: &str, sii: &[u8]) -> Result<VerifyReport, VerifyError> that parses both inputs and compares them on: Identity (vendor / product / revision), the assigned PDO index list per direction, and the mailbox bootstrap configuration (CoE/EoE/FoE supported sets).
Requirement: Diagnostic output names the differing field REQ_0561
status: open
satisfies: FEAT_0057
is verified by: TEST_0461

When a verification fails, the VerifyReport shall name each differing field with both the ESI-side and SII-side values (e.g. Identity.revision: esi=0x00100000 sii=0x00110000) rather than reporting only “mismatch”.
Requirement: Verifier reuses the parser REQ_0562
status: open
satisfies: FEAT_0057
is verified by: TEST_0462

The verifier shall consume the same EsiFile IR produced by ESI parser (FEAT_0051) and shall not maintain a second parse path. SII binary decoding lives inside the verifier crate (no reuse from ethercrab — the verifier shall not depend on ethercrab per Backend crate is the sole e... (REQ_0520)).
Requirement: Verifier exits non-zero on mismatch REQ_0563
status: open
satisfies: FEAT_0057
is verified by: TEST_0463

When invoked as a binary (ethercat-esi-verify <xml> <sii>), the verifier shall exit 0 on match, 1 on any field mismatch, and 2 on parse or I/O errors. CI gates may then cargo run -p ethercat-esi-verify -- ... as a pre-merge check.