ESLint workflow for PRs and result upload

[mirmirmirr]

Added ESLint workflow to run on all pull requests and added conditional for uploading results.

[github-advanced-security]

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[Copilot]

Pull Request Overview

This PR adds ESLint and Prettier integration to the CI/CD pipeline by creating a new code quality workflow that runs on all pull requests and pushes to main branches. The workflow outputs results in SARIF format for GitHub's security events.

• Added ESLint/Prettier workflow to run on PRs and main branch pushes
• Integrated Prettier as an ESLint plugin with error-level enforcement
• Added CodeQL Advanced workflow for security scanning

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
package.json	Added ESLint formatters and Prettier plugin dependencies
eslint.config.mjs	Integrated Prettier plugin into ESLint configuration
app/ui/components/weekday-calendar.tsx	Removed unused inDrawer parameter
app/ui/components/selectors/time-selector.tsx	Changed let to const for immutable array
README.md	Removed extra blank line
.github/workflows/formatting.yml	Replaced auto-formatting workflow with ESLint/Prettier checking workflow
.github/workflows/codeql.yml	Added CodeQL Advanced security scanning workflow
.gitattributes	Added line ending normalization to LF

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[jzgom067]

Is this supposed to be merging into main or main-preview?

[mirmirmirr]

I rebased it to main-preview