Add multiproof deployment guide

[leopoldjoy]

Adds scripts/multiproof/README.md documenting the end-to-end NoNitro dev deployment flow on Sepolia, including:

• Prerequisite setup and deploy-config requirements
• Contract deployment via DeployDevNoNitro.s.sol
• Setting a fresh anchor state post-deployment
• Deriving an Ethereum address from the enclave's raw public key
• Registering a dev signer via addDevSigner()
• Clear warnings about the dev/test-only nature of this path

Leaves a placeholder section for the WithNitro path.

[cb-heimdall]

✅ Heimdall Review Status

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Reviews	✅ 1/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1