fix: docs corrections and dead code cleanup

[dorukardahan]

Summary

Small fixes found during SDK audit — all verified against source code.

Changes

1. README: Node.js version mismatch

• README said >= 22.0.0, package.json says >= 20.0.0, CI tests both 20.x and 22.x
• Fixed to >= 20.0.0

2. getRequestHeaders JSDoc example (broker.ts)

The @example had two bugs:

• Called getServiceMetadata instead of getRequestHeaders for the headers call
• Passed non-existent serviceName parameter

- const headers = await broker.getServiceMetadata(providerAddress, serviceName, content);
+ const headers = await broker.inference.getRequestHeaders(providerAddress, content);

Also fixed role: "system" → role: "user" and headers placement in the OpenAI SDK call.

3. Dead code in response.ts

Duplicate if (!chatID) check — line 38 already returns null, so the second check at line 54 was unreachable:

- if (!chatID) {
-     throw new Error('Chat ID does not exist')
- }

Also replaced 3 console.warn calls with the existing logger.warn import (per CLAUDE.md SDK rules).

4. Commented-out import in request.ts

Removed // import { Verifier } from './verifier'

Verification

All changes verified against actual TypeScript signatures before committing. No behavioral changes — only docs and dead code removal.

🤖 Generated with Claude Code

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