Add post-action handling

[dzmbs]

Description

The protocol currently lacks a fallback mechanism to execute tasks post-action completion (e.g., API calls, database writes, referral tracking). Adding this feature would enable secondary processes like analytics, notifications, or other external logic to be triggered after the main action is finalized.

Suggested Solution

Introduce a postAction handler within each action type to define tasks that execute upon successful action completion.

Example postAction Structure:

export interface PostAction {
    type: 'api-call' | 'db-write' | 'smart-contract';
    endpoint?: string; // For API calls
    data?: string;     // Payload for API or DB write
    contractAddress?: string; // For smart contract call
    abi?: string; // ABI for contract interaction
}