feat: integrate AWS Comprehend as a PII redaction utility (#290)

[tarai-dl]

Summary

Integrates AWS Comprehend as a utility to redact PII (Personally Identifiable Information) from text, addressing bounty issue #290.

Changes

• New module: @arakoodev/edgechains.js/redactor with ComprehendPiiRedactor class
• PII detection: Uses AWS Comprehend DetectPiiEntities API to identify sensitive data
• Multiple redaction modes: REPLACE_WITH_ENTITY_TYPE, REDACT, MASK_WITH_CHARACTER
• Chainable API: Works as observable/middleware with existing Endpoint classes
• 10 unit tests: Comprehensive test coverage with mocked AWS responses
• Working example: Full demo in examples/pii-redactor/

Supported PII Types

NAME, EMAIL, PHONE, SSN, CREDIT_DEBIT_CARD_NUMBER, BANK_ACCOUNT_NUMBER, ADDRESS, DATE_OF_BIRTH, DRIVER_ID, PASSPORT_NUMBER, IP_ADDRESS

Usage

import { ComprehendPiiRedactor } from "@arakoodev/edgechains.js/redactor";

const redactor = new ComprehendPiiRedactor();

// Detect PII
const entities = await redactor.detectPiiEntities("My email is john@example.com");

// Redact PII
const result = await redactor.redact({
    text: "My name is John Smith",
    maskMode: "REPLACE_WITH_ENTITY_TYPE",
});

// Chain with LLM endpoint
const safeChat = redactor.chainWith(openai.chat.bind(openai));

Closes

Closes #290

Video Demo

A Loom video demonstrating the working example will be added once reviewed.

[github-actions]

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