Extract shared comment logic; add Azure DevOps adapter

[tupe12334]

Summary

Implements the refactor + adapter part of #1:

• Extracts the platform-agnostic comment body into src/comment.mjs (buildCommentBody({ owner, repo, issue })), matching the issue's proposed shared module.
• Moves the GitHub Actions logic into src/github/index.mjs. Behavior is unchanged — it still guards on issues.opened, reads the same context, and posts via Octokit the same way. dist/index.mjs was rebuilt from the new entrypoint (ncc build src/github/index.mjs) and action.yml still points at dist/index.mjs, so the published action's behavior is identical.
• Adds src/azure/index.mjs, an Azure DevOps adapter that posts to the Work Item Comments REST API using PAT auth (Basic auth, empty username), reusing buildCommentBody from the shared module. Includes unit tests with a mocked fetch.
• Adds node --test-based unit tests (Node's built-in test runner — no new dependency) for comment.mjs and the Azure adapter's HTTP call, plus a test script in package.json.

Deliberately left out (follow-up)

The issue itself flags several open design questions that this PR does not resolve, since they need a decision rather than a default:

• Trigger wiring: Azure DevOps pipelines don't natively fire on "work item created" the way GitHub Actions fires on issues.opened — that needs either a service hook (webhook) or a dedicated pipeline task definition. The adapter is written to be called once those env vars (AZURE_DEVOPS_ORG, SYSTEM_TEAMPROJECT, WORKITEM_ID, AZURE_DEVOPS_TOKEN, BUILD_REPOSITORY_NAME) are populated by whatever trigger mechanism is chosen, but it is not wired into a new action.yml/pipeline task, a build step, or CI here.
• Auth: implemented PAT (Basic auth) only, as the simplest option per the ADO REST API docs. Service-connection auth (OAuth/token exchange) is not implemented — no consumer for it yet.
• Whether the Azure adapter ships as a separate GitHub Action/repo or a new entry point in this repo — left as-is (new entry point in this repo, unwired) pending a decision.

Test plan

• pnpm test — all unit tests pass (comment.mjs, azure/index.mjs)
• pnpm lint — clean
• pnpm build — regenerates dist/index.mjs from the new src/github/index.mjs entrypoint; diffed the output to confirm the GitHub adapter logic is unchanged, just re-composed through comment.mjs

Relates to #1

This pull request was opened by the Open issues → fix PRs (owned repos + my orgs) routine of moadim.