docs: add How OnchainKit Works overview section

[devacc8]

Summary

Added a "How OnchainKit Works" section to help new developers understand the architecture and relationships between components.

Changes

• Visual ASCII diagram showing component hierarchy
• Core Building Blocks table with modules, purposes, and key components
• Data Flow explanation in plain language
• Getting started tip

Preview

┌─────────────────────────────────────────────────────────┐
│                  OnchainKitProvider                     │
│  (Wraps your app, provides config & wallet connection)  │
└─────────────────────────────────────────────────────────┘
                            │
        ┌───────────────────┼───────────────────┐
        ▼                   ▼                   ▼
┌───────────────┐   ┌───────────────┐   ┌───────────────┐
│    Wallet     │   │   Identity    │   │  Transaction  │
└───────────────┘   └───────────────┘   └───────────────┘

Module	Purpose	Key Components
Wallet	Connect wallets, manage accounts	<Wallet>, <ConnectWallet>
Identity	Display ENS/Basename, avatars	<Identity>, <Avatar>, <Name>
Transaction	Build and send transactions	<Transaction>, <TransactionButton>

Fixes #2580

[vercel]

@devacc8 is attempting to deploy a commit to the Coinbase Team on Vercel.

A member of the Team first needs to authorize it.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	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 1 Sum 2

[cb-heimdall]

Review Error for JoeJMorrris @ 2026-01-25 04:28:56 UTC
User failed mfa authentication, either user does not exist or public email is not set on your github profile. \ see go/mfa-help

[cb-heimdall]

Review Error for JoeJMorrris @ 2026-01-25 04:29:06 UTC
User failed mfa authentication, either user does not exist or public email is not set on your github profile. \ see go/mfa-help