☕ feat: Prevent Screen Sleep During Response Generation

[michnovka]

Summary

Prevent Screen Sleep While Responses Stream - fixes #10290

• add a reusable useWakeLock hook that requests the browser screen wake lock whenever LibreChat is actively generating a reply, re-acquiring after releases or tab visibility changes
• expose anySubmittingSelector and a headless WakeLockManager that observes submission state so the wake lock is managed globally without touching chat components
• mount the manager inside App so every conversation benefits automatically, keeping displays awake until generation completes

This keeps long-running generations from pausing when the device tries to go idle.

Change Type

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Translation update

Testing

Please describe your test process and include instructions so that we can reproduce your test. If there are any important variables for your testing configuration, list them here.

Test Configuration:

Checklist

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• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective or that my feature works
• Local unit tests pass with my changes
• Any changes dependent on mine have been merged and published in downstream modules.
• A pull request for updating the documentation has been submitted.

[michnovka]

@danny-avila fixed eslint, please rerun workflows. Thanks!