Avoid prototype-polluting assignments in local data providers

[WiXSL]

Summary

• Add tests on prototype ppollution prevention

Why

GitHub code scanning reports four Prototype-polluting assignment alerts:

• #49
• #50
• #51
• #52

These alerts are false positive since we check resource name on all resources
Added tests to on the check

Testing

• yarn test-unit --runTestsByPath packages/ra-data-local-storage/src/index.spec.ts packages/ra-data-local-forage/src/index.spec.ts

[Copilot]

Pull request overview

This PR addresses prototype-pollution risks reported by code scanning in the local data providers by routing resource collection writes through safer helpers and adding regression tests for safe collection creation and invalid resource keys.

Changes:

• Replace dynamic data[resource] = [] and data[resource][index] = ... mutations with safer collection accessors (getResourceCollection, getOrCreateResourceCollection) and array mutation helpers.
• Apply the same approach to both ra-data-local-storage and ra-data-local-forage providers for create/update/delete flows.
• Add new unit tests covering safe creation of missing collections and rejection of unsafe resource keys.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 8 comments.

File	Description
packages/ra-data-local-storage/src/index.ts	Routes write operations through validated resource collections and avoids direct prototype-polluting assignments.
packages/ra-data-local-storage/src/index.spec.ts	Adds regression tests for safe collection creation and unsafe resource key rejection.
packages/ra-data-local-forage/src/index.ts	Mirrors the safer collection write approach for localForage-backed storage.
packages/ra-data-local-forage/src/index.spec.ts	Adds regression tests for safe collection creation and unsafe resource key rejection.

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[ThieryMichel]

A simpler and more straightforward fix would be to check that resource === 'proto' and throw an error when it is.
Also add comment to explain the reason.
Need to see if this will content codeql though