refactor(storage): route lambda access through storage providers

[edersonbrilhante]

Description

Move Lambda GitHub App credentials and runner configuration access behind the shared storage-provider interfaces. Control-plane and termination-watcher tests now mock provider contracts, while SSM-specific behavior remains covered by the SSM storage-provider tests. The legacy control-plane SSM housekeeper wrappers were removed and the housekeeper test was moved under the SSM provider.

Test Plan

• Ran the termination-watcher deregistration tests: 13 passed
• Ran the SSM GitHub App credentials provider tests: 7 passed
• Ran ESLint on the changed termination-watcher files
• Ran TypeScript compilation for termination-watcher
• Ran Prettier checks on the changed termination-watcher files
• Verified the targeted diff with git diff --check

Related Issues

Not applicable.

[github-actions]

Dependency Review

The following issues were found:

• ✅ 0 vulnerable package(s)
• ✅ 0 package(s) with incompatible licenses
• ✅ 0 package(s) with invalid SPDX license definitions
• ⚠️ 1 package(s) with unknown licenses.

See the Details below.

License Issues

lambdas/functions/termination-watcher/package.json

Package	Version	License	Issue Type
@aws-github-runner/storage-providers		Null	Unknown License

OpenSSF Scorecard

Package	Version	Score	Details
npm/@aws-github-runner/storage-providers		Unknown	Unknown

Scanned Files

• lambdas/functions/control-plane/package.json
• lambdas/functions/termination-watcher/package.json