fix: lower Base Sepolia OBOL faucet default amount

[bussyjd]

Summary

• Lowers the default Base Sepolia OBOL faucet display/config amount from 100 OBOL to 5 OBOL in the stack frontend values.
• Keeps runtime env override support unchanged.
• Aligns contracts/fork-obol Foundry/docs to solc 0.8.24, matching the deployed Base Sepolia token/faucet bytecode verified via Sourcify.

Context

• PR feat: wire Base Sepolia OBOL faucet env #447 merged the deployed Base Sepolia OBOL token/faucet addresses and initially kept the faucet amount at 100 OBOL.
• The live owner wallet has now updated the faucet on-chain to 5 OBOL per claim with the existing 86400 second cooldown.
• This PR aligns the stack runtime default and the fork-obol deployment docs with the current deployed state.

Live deployed state

• Token: 0x0a09371a8b011d5110656ceBCc70603e53FD2c78
• Faucet: 0x0c8Ec594d067d1D850deba7BAa05d4052Ab97076
• On-chain claim amount: 5 OBOL
• Cooldown: 86400 seconds
• Owner after transfer:
  • token: 0x1Adf1208feB12A2D785e842d35C09132850F1231
  • faucet: 0x1Adf1208feB12A2D785e842d35C09132850F1231
• Faucet balance after the claim-terms update: 50,000 OBOL
• Claim-terms update tx: 0x559eb0b368323382a555ca72633e2e1ff9359aef4be54ba6d0fc414ccaf91d39

Runtime env default

BASE_SEPOLIA_OBOL_TOKEN_ADDRESS=0x0a09371a8b011d5110656ceBCc70603e53FD2c78
BASE_SEPOLIA_OBOL_FAUCET_ADDRESS=0x0c8Ec594d067d1D850deba7BAa05d4052Ab97076
BASE_SEPOLIA_OBOL_FAUCET_AMOUNT="5 OBOL"

Related: #406

Validation

• Follow-up local validation for the compiler/doc alignment change in this PR:
  • git diff --check
  • forge build
• GitHub checks rerun on the updated branch push.