ci: add dedicated ESLint workflow

[Copilot]

Adds ESLint enforcement as a CI check for all PRs, per CI/CD Gap Assessment (Discussion #227).

Changes

• New workflow at .github/workflows/lint.yml
• Triggers on pushes to main and PRs targeting main
• Ignores markdown-only changes via paths-ignore
• Uses pinned actions consistent with existing workflows
• 5-minute timeout (typical execution < 1 minute with npm caching)

Note

Repository admin should add this workflow as a required status check in branch protection settings to enforce linting on PR merges.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[High Priority] Add dedicated ESLint CI workflow</issue_title>
<issue_description>## Context
From CI/CD Pipeline Gap Assessment (Discussion #227)

Description

Create a dedicated workflow for ESLint enforcement to ensure code quality standards are met on all PRs.

Acceptance Criteria

• Create new lint workflow file
• Configure ESLint to run on all TypeScript files
• Make workflow required for PR merges
• Ensure fast feedback (target < 1 minute)

Estimated Effort

Approximately 2 hours

Related

• Discussion CI/CD Pipeline and Integration Tests - Gap Assessment #227</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [High Priority] Add dedicated ESLint CI workflow #231

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[github-actions]

Test Coverage Report

Metric	Coverage	Covered/Total
Lines	77.19%	1300/1684
Statements	77.27%	1333/1725
Functions	77.17%	142/184
Branches	69.76%	450/645

Coverage Thresholds

The project has the following coverage thresholds configured:

• Lines: 38%
• Statements: 38%
• Functions: 35%
• Branches: 30%

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Coverage report generated by `npm run test:coverage`