feat(mainnet,sepolia): add task to update min base fee to 5M wei

[niran]

Updates the minBaseFee parameter from 2,000,000 wei to 5,000,000 wei (2.5x increase) on both mainnet and Sepolia.

Also updates OP_COMMIT to match the post-U18 SystemConfig implementation (d6aa14e).

Script is identical to mainnet/2026-01-28-update-min-base-fee/script/SetMinBaseFee.s.sol.

Parameters

Parameter	From	To
minBaseFee	2,000,000 wei	5,000,000 wei

Validation

Updates storage slot:

• 0x6c: minBaseFee from 2,000,000 (0x1E8480) to 5,000,000 (0x4C4B40)

Includes rollback task that reverts to previous value if needed.

Sepolia task

The Sepolia task (sepolia/2026-02-17-update-min-base-fee) differs from the mainnet task in:

• SYSTEM_CONFIG, OWNER_SAFE, and SENDER addresses
• LEDGER_ACCOUNT default (1 vs 0)
• --ledger-id passed to the signer tool to match LEDGER_ACCOUNT

The script, foundry.toml, and README are unchanged.

[cb-heimdall]

✅ Heimdall Review Status

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