Add dependency-free AWS Comprehend PII redactor

[robin081412108-coder]

Summary

• Add AWSComprehendRedactor to the JS AI package with direct PII detection/redaction through AWS Comprehend.
• Keep runtime dependency-free by signing Comprehend REST requests with Node built-ins instead of adding the AWS SDK.
• Support injectable mock clients, direct text redaction, prompt/message redaction before endpoint chat() calls, and Observable-style chaining via redactText$ / redactTextOperator().
• Export the redactor and types from @arakoodev/edgechains.js/ai.
• Add mocked Vitest coverage and a runnable example under JS/edgechains/examples/aws-comprehend-redaction.

Demo

Demo video/GIF:

The example can be run without AWS credentials using its offline mock client:

cd JS/edgechains/examples/aws-comprehend-redaction
npm install
npm start

Expected demo output is documented in JS/edgechains/examples/aws-comprehend-redaction/README.md and shows direct redaction plus chainEndpoint() forwarding a sanitized prompt.

Validation

• C:\Users\robin\Documents\Codex\2026-05-23\github-50\tooldeps-ts\node_modules\.bin\vitest.cmd run JS/edgechains/arakoodev/src/ai/src/tests/awsComprehendRedactor.test.ts -> 5 passed
• C:\Users\robin\Documents\Codex\2026-05-23\github-50\tooldeps-ts\node_modules\.bin\tsc.cmd --noEmit --target ES2022 --module NodeNext --moduleResolution NodeNext --strict --skipLibCheck --esModuleInterop --typeRoots C:\Users\robin\Documents\Codex\2026-05-23\github-50\tooldeps-ts\node_modules\@types --types node JS/edgechains/arakoodev/src/ai/src/lib/aws-comprehend/awsComprehendRedactor.ts JS/edgechains/arakoodev/src/ai/src/lib/aws-comprehend/index.ts -> passed
• npm start from JS/edgechains/examples/aws-comprehend-redaction -> passed
• git diff --cached --check -> passed before commit

/claim #290

Closes #290

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[robin081412108-coder]

I have read the Arakoo CLA Document and I hereby sign the CLA

[robin081412108-coder]

recheck

[robin081412108-coder]

Added a short demo GIF to the PR description:

https://raw.githubusercontent.com/robin081412108-coder/EdgeChains/demo-assets/aws-comprehend-redaction-545/aws-comprehend-redaction-demo.gif

I also pushed a follow-up commit to make the example runnable from a local checkout with:

cd JS/edgechains/examples/aws-comprehend-redaction
npm install
npm start

Validation completed:

• npm start from JS/edgechains/examples/aws-comprehend-redaction passes
• vitest run JS/edgechains/arakoodev/src/ai/src/tests/awsComprehendRedactor.test.ts passes with 5 tests