Fix container mapping for Docker 29 and surface failures

[Copilot]

Summary

• Read pushed image IDs with docker events --format ID={{.Actor.ID}} instead of the removed top-level .ID field, preserving the existing ID=... report format.
• Surface container-mapping failures through the Azure Pipelines task library's warning API while keeping the injected task non-blocking.
• Add regression coverage for the event command, encoded and JSON reports, Docker event/image failures, and successful runs with no push events.
• Update the container-mapping test harness to await the supported mock runner API and mock HTTPS token/report requests rather than attempting real network calls.
• Document Docker compatibility and the non-blocking warning behavior.

Fixes #172.

Validation

• npm run compile passed.
• node_modules/.bin/tsc --project test/tsconfig.json --outDir test/lib passed.
• node_modules/.bin/mocha test/lib/MicrosoftSecurityDevOps/v1/container-mapping.tests.js test/lib/MicrosoftSecurityDevOps/v1/command-executor.tests.js passed: 11 tests.
• Before the production fix, the new Actor ID and warning assertions failed against the original implementation.

The configured package registry rejected dependency installation with HTTP 401. For local validation, the task library was built from its public v1.13.0 source tag and installed locally, along with the missing mockery test helper. Dependency manifests and lockfiles are unchanged. Validation used mocked Docker/HTTPS calls, not a live Azure DevOps pipeline.