feat: add push-protocol-notification-tutorial

[jadonamite]

Summary

Adds a cookbook guide for integrating Push Protocol to send on-chain notifications from a Base smart contract.

Content

• Author: @jadonamite
• Stack: Push Protocol, Solidity, Foundry.
• Key Features:
  • IPUSHCommInterface.sol definition.
  • NotificationSender.sol implementing the sendNotification call.
  • Detailed "Delegation" workflow (authorizing the contract to send messages).
  • Payload formatting guidelines for Push Identity V2.

Motivation

Notifications are essential for dApp UX. This guide empowers Base developers to programmatically alert users about on-chain events (liquidations, DAO proposals, transfers) directly from the smart contract layer.

Verification

• Verified sendNotification function signature matches Push V1.5/V2 interface.
• Verified payload construction (0+3+...) logic.
• Verified delegation requirement in Push Protocol architecture.

[cb-heimdall]

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