improve: fix eslint config sourceType, add devDependencies, add node_modules to gitignore

[Coding-Dev-Tools]

Automated improvement by dev-engineer

• Fixed eslint.config.mjs sourceType from 'commonjs' to 'module' (file uses ESM import syntax)
• Added devDependencies (@eslint/js, eslint, globals) to package.json
• Removed duplicate devDependencies key from package.json
• Added node_modules/ to .gitignore

[github-actions]

🤖 Automated Code Review

✅ Ruff Lint — No issues

⚠️ Ruff Format — Formatting needed

Would reformat: src/configdrift/cli.py
Would reformat: src/configdrift/diff.py
Would reformat: src/configdrift/loader.py
Would reformat: tests/test_cli.py
Would reformat: tests/test_coverage_gaps.py
Would reformat: tests/test_diff.py
Would reformat: tests/test_loader.py
7 files would be reformatted, 2 files already formatted

✅ Secret Detection — Clean

✅ Large Files — Within limits

📊 Diff Stats — 3 file(s) changed

 .gitignore        |   1 +
 eslint.config.mjs |   2 +-
 package.json      | 107 +++++++++++++++++++++++++++---------------------------
 3 files changed, 56 insertions(+), 54 deletions(-)

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Verdict: ⚠️ Warnings — Lint/format issues found. Recommend fixing before merge.

Automated by Coding-Dev-Tools/.github reusable workflow.