Add scenario access list support with placeholder resolution

[jelias2]

Summary

Builds on #581 to address @zeroXbrock's reviewer feedback: allow {placeholder} strings in access list address and storageKeys.

PR #581 currently uses alloy's typed AccessListItem on both the loose and strict sides, which cannot hold placeholder strings during the loose-to-strict conversion phase. This PR:

• Adds LooseAccessListItem { address: String, storage_keys: Vec<String> } on the loose side (keeps storageKeys camelCase from Add scenario access list support #581).
• Keeps the strict side as alloy's typed AccessListItem (per @zeroXbrock's design).
• Resolves placeholders in make_strict_call via the existing templater + DB-driven map, parsing into Address / B256.
• Extends find_fncall_placeholders to scan access list strings so the DB lookup pre-populates referenced contract addresses.
• openrpc.json regenerated by cli/build.rs.

Example

[[spam.tx.access_list]]
address = "{SpamMe5}"
storageKeys = [
    "{testkey1}",
    "{testkey2}",
]

Relationship to #581

This branch was built on top of #581 (scenario-access-list-support, head 6460cb4). If #581 is the preferred merge vehicle, this PR could be re-targeted at karlfloersch's branch so the placeholder support lands inside the existing review thread. Filing here against main as the more flexible default — happy to retarget.

Tests

• cargo +1.94 test -p contender_core access_list --lib — 3 passed
• cargo +1.94 test -p contender_testfile --lib — 22 passed
• cargo +1.94 fmt --check — clean
• Two new placeholder tests added:
  • access_list_parses_placeholders_from_toml (contender_core)
  • parses_spam_tx_access_list_with_placeholders_toml (contender_testfile)
• Release binary built and smoke-tested via an external benchmarker invocation against a real devnet for backwards compatibility.

Test plan

• Unit tests in both crates pass
• cargo fmt --check clean
• Backwards compat: existing scenarios without access_list still build and broadcast correctly
• Manual: scenarios with hard-coded address + storageKeys still work (no placeholder)
• Manual: scenarios with {Contract} placeholder for address resolve correctly
• Manual: scenarios with {slot} placeholder for storage keys resolve correctly
• Reviewer test against an L2 with EIP-2930 enforcement