feat: drop eth1 data and deposits from Heze containers (EIP-8015)

[barnabasbusa]

EIP-6110 moved validator deposits to the execution layer, and once the transition completes (eth1_deposit_index == deposit_requests_start_index) the legacy deposit fields are permanently unused; EIP-8015, added to Heze in consensus-specs v1.7.0-beta.4, removes them. This drops eth1_data and deposits from the Heze BeaconBlockBody (progressive container gaps 1 and 6) and eth1_data, eth1_data_votes, eth1_deposit_index and deposit_requests_start_index from the Heze BeaconState (gaps 8, 9, 10 and 28), regenerates the SSZ code for spec/heze and spec/all, updates the JSON/YAML encodings, and makes the versioned ETH1Data(), Deposits() and DepositRequestsStartIndex() getters return an error for Heze.

🤖 Generated with Claude Code

[barnabasbusa]

Also fixes Heze execution_payload_availability JSON/YAML encoding (was a list of decimal strings, now hex like Gloas); the mainnet Heze BeaconState ssz_static vectors failed to decode without it.

[redpandabot]

The PR implements EIP-8015 for Heze by dropping eth1_data/deposits from BeaconBlockBody and the eth1/deposit-index fields from BeaconState, regenerating SSZ for spec/heze and spec/all, updating JSON/YAML, and making the versioned ETH1Data/Deposits/DepositRequestsStartIndex getters error for Heze. The follow-up commit aligns Heze execution_payload_availability JSON encoding with Gloas. I traced the progressive-container gaps, the generated inactive-field placeholders and active-fields bitvectors, and the JSON/YAML/versioned paths and found no in-scope defects.

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_{Reviewed 16 changed file(s) @ c596ad60 — no blocking issues found.
"In theory, there is no difference between theory and practice. In practice, there is." — attributed to Yogi Berra}