feat(ingest): EVM deposit detection via ERC-20 Transfer logs

[Malik6828]

Scans eth_getLogs for registered token contracts with a block-number cursor, advancing only after durable processing so a crash resumes exactly-once, the same guarantee the Horizon path gives.

Logs are matched on the emitting contract address, not topics alone: any contract can emit a Transfer event with arbitrary topics, so topic-only attribution would let an attacker mint balances for free. This is the primary security invariant in this module.

Deposits are recorded as 'unconfirmed'; crediting is gated on #222. Merging #221 before #222 cannot create spendable balances, enforced at the DB level, not by convention.

Changes:

• crates/ingest/src/evm.rs: EvmIngestor (process_log, poll_once, run), EvmRpcClient (eth_blockNumber, eth_getLogs), EvmLog decoding, RegisteredToken registry, adaptive range bisection on RangeTooLarge.
• crates/store/migrations/0021_evm_ingest.sql: chain_id + block_number on ingest_cursor; chain_id + evm_log_index on transactions; uq_tx_evm_onchain dedup index; 'unconfirmed' status value.
• crates/store/src/lib.rs: get_evm_cursor, set_evm_cursor, mark_evm_polled, record_evm_deposit, evm_address_by_hex, NewEvmDeposit struct.
• crates/ingest/tests/evm_ingest_tests.rs: 10 integration tests covering happy path, adversarial fake Transfer (critical security), idempotency/replay, crash-resume cursor, quarantine of unregistered tokens, range bisection, removed (reorged) logs, non-deposit address filtering, and unconfirmed-status invariant.
• docs/ingest-integration.md: EVM section documenting native ETH scope decision, contract address verification, cursor contract, unconfirmed status, adaptive bisection, schema changes, and tests.

All 34 unit tests + 10 EVM integration tests pass; full workspace builds cleanly with no regressions.

Refs #221

Summary

Related step / issue

Checklist

• cargo fmt --all -- --check passes
• cargo clippy --workspace --all-targets -- -D warnings passes
• cargo test --workspace passes
• No secrets (seeds/keys) logged or persisted in plaintext
• Added/updated tests (test vectors for crypto/derivation changes)
• Updated docs / CHANGELOG if behavior changed

How to test

Closes

closes #221