Add OutreachAgent

[pagefarms]

Summary

• Add OutreachAgent under Email Infrastructure → Purpose-built for agents.
• Describe its reply-aware outbound workflows, delivery state, signed webhooks, retries, and sender guardrails.
• Link the public TypeScript SDK install and agent integration guide.

Fit and validation

• Purpose-built for AI-agent outbound email workflows.
• @outreachagent/sdk-ts is publicly available on npm; the product and agent guide links return successfully.
• I intentionally did not list the MCP package because its documented npm package is not currently public.
• The README diff is scoped to one entry and follows the requested format.

Disclosure: I maintain OutreachAgent.