feat: add Creator module for cross-chain tipping and creator monetization

[spiritclawd]

Summary

Add a Creator Module that enables embeddable tipping and creator monetization with cross-chain payment support. This positions starkzap as the "Stripe for Web3" and helps break starkzap out of the Starknet bubble by solving a real problem for non-Starknet developers.

Motivation

• Patreon has 8M+ creators, but only ~2% use crypto (friction too high)
• Creators do not care about chains — they care about getting paid
• A simple "Tip Button" that works cross-chain would onboard creators to Starknet without them needing to understand account abstraction
• Once they embed the tip button, they become Starknet users

Proposed API

import { StarkZap, Creator } from "starkzap";

// Initialize creator module
const creator = new Creator({
  starknetAddress: "0x...",
  displayName: "MyAwesomeCreator",
});

// Generate embeddable tip button
const tipButton = creator.tipButton({
  tokens: ["USDC", "STRK", "ETH"],
  chains: ["base", "arbitrum", "starknet"],
  suggestedAmounts: ["1", "5", "10", "25"],
});

// Embed in website
const html = tipButton.render();

Features

Phase 1: Core Tipping

• Creator class for managing creator profiles
• tipButton() - Generate embeddable tip button HTML/component
• Cross-chain payments via ChainRails integration (builds on feat(payment): add Chainrails cross-chain payment module #51)
• Gasless tipping on Starknet via paymaster
• One-time tips with custom amounts

Phase 2: Subscriptions

• Recurring tips/subscriptions (monthly, yearly)
• Membership tiers with benefits
• Creator dashboard for analytics

Phase 3: Creator Tokens

• Creator tokens for engagement rewards
• Social features (top supporters leaderboard)

Use Cases

1. Blog/Newsletter Tips - Embed tip button in articles
2. Stream Donations - Real-time tips during livestreams
3. Guild Support - Allow members to support gaming guilds
4. Open Source Tips - Tip project maintainers directly

Technical Implementation

src/creator/
├── index.ts          # Exports
├── creator.ts        # Creator class
├── tip-button.ts     # Embeddable tip button component
├── subscription.ts   # Subscription management
└── types.ts          # Type definitions

Integration Points

• ChainRails (feat(payment): add Chainrails cross-chain payment module #51) - Cross-chain payment routing
• Paymaster - Gasless transactions on Starknet
• Account Abstraction - Seamless UX for first-time users

Why This Matters

Current State	With Creator Module
Starknet-only SDK	Cross-chain payment solution
500K potential users	8M+ creators + their audiences
Developer-focused	Creator-focused (larger market)
High-friction onboarding	Embed button, start earning

Target Metrics

• 100+ websites embedding starkzap tip buttons in first 3 months
• 1000+ tips processed across chains
• Viral adoption through creator networks

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This is a strategic feature that could become the flagship use case for starkzap, driving adoption far beyond the current Starknet ecosystem.