feat(ws): implement x402 over WebSocket

[web3luka]

Description

This PR introduces WebSocket transport support for x402 in TypeScript via a new @x402/ws package.

Scope

• add x402WSClient with automatic 402 -> payment -> retry flow
• add x402WSServer with RPC-style WS request/response dispatching
• add createWSPaymentWrapper for server-side payment verify/settle around handlers
• add real EVM integration test for end-to-end paid WS call
• add real SVM integration test for end-to-end paid WS call
• add package setup/docs/scripts needed to build and test @x402/ws

Tests

Executed locally:

• pnpm --filter @x402/ws lint
• pnpm --filter @x402/ws test
• pnpm --filter @x402/ws test:integration

Integration run confirms successful paid WS flow and settlement with transaction output.

Checklist

• I have formatted and linted my code
• All new and existing tests pass

• My commits are signed (required for merge)
• I added a changelog fragment for user-facing changes (docs-only changes can skip)

[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 0 Sum 1

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