docs: Refactor sample to stop and start Cloud SQL instances

[camiekim]

Description

• Migrate tutorial from GCE instances to Cloud SQL for SQL Server instances
• Update Cloud Functions to use 2nd gen Node.js functions with Eventarc triggers

Fixes b/525850307 (cl/940615883)

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• [x ] I have followed guidelines from CONTRIBUTING.MD and Samples Style Guide
• [x ] Tests pass: npm test (see Testing)
• [x ] Lint pass: npm run lint (see Style)
• Required CI tests pass (see CI testing)
• These samples need a new API enabled in testing projects to pass (let us know which ones)
• These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• This pull request is from a branch created directly off of GoogleCloudPlatform/nodejs-docs-samples. Not a fork.
• This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• This sample adds a new sample directory, and I created GitHub Actions workflow for this sample
• This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• [x ] Please merge this PR for me once it is approved

Note: Any check with (dev), (experimental), or (legacy) can be ignored and should not block your PR from merging (see CI testing).

[gemini-code-assist]

Code Review

This pull request migrates the scheduling sample from Google Compute Engine (GCE) instances to Cloud SQL instances, updating the README, dependencies, function implementation to use CloudEvents, and the corresponding unit tests. The review feedback highlights a critical syntax error in the test file (a stray cd command), inconsistent multiline string formatting in a log statement, and an opportunity to improve input validation by ensuring the label payload attribute is a string containing an = delimiter before splitting.