3.5: Upgrade / migrate from Eslint to biome

[camd]

Summary

This PR migrates from ESLint + Prettier to Biome, a fast, unified linter and formatter.

Why Biome?

pnpm Compatibility Issues with ESLint:

• ESLint's plugin ecosystem has poor compatibility with pnpm's strict node_modules structure
• eslint-config-airbnb doesn't support ESLint 9's flat config, requiring the FlatCompat compatibility layer
• Multiple unmet peer dependency warnings due to phantom dependencies

Biome Benefits:

• ~100x faster - lints 383 files in ~50ms vs several seconds with ESLint
• Single dependency - replaces 12 ESLint/Prettier packages (164 total packages removed)
• No plugin ecosystem - all rules are built-in, eliminating peer dependency issues
• Unified tool - linting and formatting in one tool with consistent configuration
• pnpm-friendly - no compatibility layer or plugin resolution issues

What Changed

Removed:

• eslint and all eslint-* plugins/configs (12 packages)
• prettier
• @babel/eslint-parser
• globals
• eslint.config.mjs

Added:

• @biomejs/biome
• biome.json configuration

Updated Scripts:

Old	New
eslint ...	biome lint
prettier --write	biome format --write
prettier --check	biome format
-	biome check (lint + format)

Auto-fixed by Biome:

• Removed unused import React from 'react' statements (151 files) - React 17+ doesn't require explicit React imports for JSX

Test Plan

• pnpm lint passes (0 errors, 9 warnings)
• pnpm format:check works
• pnpm test passes (existing InfraCompare test failure is unrelated)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 67.42909% with 356 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.16%. Comparing base (a82c683) to head (5a4b9eb).

Files with missing lines	Patch %	Lines
ui/job-view/pushes/Push.jsx	65.31%	77 Missing ⚠️
ui/job-view/pushes/FuzzyJobFinder.jsx	52.94%	31 Missing and 1 partial ⚠️
ui/hooks/useDebounce.js	0.00%	22 Missing and 2 partials ⚠️
ui/job-view/pushes/PushJobs.jsx	70.73%	12 Missing ⚠️
ui/intermittent-failures/DateRangePicker.jsx	0.00%	10 Missing ⚠️
ui/intermittent-failures/Layout.jsx	0.00%	10 Missing ⚠️
ui/shared/RevisionInformation.jsx	0.00%	9 Missing ⚠️
ui/job-view/pushes/PushHeader.jsx	76.47%	7 Missing and 1 partial ⚠️
ui/job-view/details/summary/SummaryPanel.jsx	0.00%	7 Missing ⚠️
ui/intermittent-failures/BugDetailsView.jsx	0.00%	5 Missing ⚠️
... and 69 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9138      +/-   ##
==========================================
+ Coverage   80.01%   81.16%   +1.15%     
==========================================
  Files         601      604       +3     
  Lines       32715    33822    +1107     
  Branches     3314     3240      -74     
==========================================
+ Hits        26178    27453    +1275     
+ Misses       6371     6215     -156     
+ Partials      166      154      -12     

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