fix: use dedicated Base Sepolia bootnode ENRs instead of mainnet's

[Lesnak1]

Summary

Refs #1154 (Bug 1 only — Bug 2 is already covered by #1155)

.env.mainnet and .env.sepolia contain byte-for-byte identical BASE_NODE_P2P_BOOTNODES values, so Sepolia nodes bootstrap consensus-layer discovery against mainnet peers instead of dedicated Sepolia peers.

Fix

Replaced the Sepolia value with the consensus bootnode ENR that base-consensus is actually built with for base-sepolia (chain_id 84532), sourced directly from base/base's crates/common/chains/src/config.rs -> SEPOLIA.bootnodes.consensus.

Verification performed

• Decoded the ENR and confirmed it is a structurally valid v4 record with IP and opstack chain tags that are disjoint from the mainnet set.
• Confirmed the new value is a match against base/base's SEPOLIA.bootnodes.consensus.
• Confirmed only a single line changed (git diff --stat).

Changes

• .env.sepolia: BASE_NODE_P2P_BOOTNODES updated to the Sepolia-specific ENR.

[cb-heimdall]

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[odisseus21]

ı thin so!

[odisseus21]

base very quality!