chore: auto-audit hygiene fixes

[itsmylife]

Automated repo hygiene audit. This branch applies the following standard changes:

• Apply npx @grafana/create-plugin@latest update (separate commit).
• Set engines in package.json to node >=24 (and npm >=11.15.0 for npm-based repos), across every package.json outside node_modules.
• Bump go.mod go (and toolchain if present) to 1.26.3.
• Set packageManager to yarn@4.15.0.
• Replace .yarnrc.yml with the standard template (enableScripts: false, npmMinimalAgeGate: 4320, etc.).

Notes

• All commits are SSH-signed.
• Audit was applied uniformly across ~70 Grafana data-source / library repos. See the audit driver (run locally) for the full ruleset.
• Please skim the diff before merging.

[github-actions]

TruffleHog Scan Results

Summary: Found 1 potential secrets (0 verified, 1 unverified)

• Possible secret (Gitlab) at .yarn/releases/yarn-4.15.0.cjs:711 → npmP***ance

Review: Check if unverified secrets are false positives.

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Ignoring False Positives:
To mark a false positive, add # trufflehog:ignore as an inline comment on the same line as the detected secret:

my_fake_secret = "AKIAIOSFODNN7EXAMPLE"  # trufflehog:ignore

This works for files that support line numbers (most source files). After adding the comment, push your changes and the scan will re-run.