feat(plugin-lighthouse): implement multiple URL support

[hanna-skryl]

Closes #1008

This PR adds support for running Lighthouse on multiple URLs to provide holistic performance and accessibility analysis across different pages.

Key Features

• Multiple URL input: Accept string | string[] | Record<string, number> for the urls parameter
• Sequential execution: Run Lighthouse on each URL sequentially
• URL-specific audits: Generate distinct audit slugs with numbered suffixes (e.g., first-contentful-paint-1, first-contentful-paint-2)
• URL-specific groups: Create separate groups for each URL with descriptive titles including the URL and slugs including numbered suffixes
• Category aggregation: Provide mergeLighthouseCategories helper to combine results across URLs
• Backward compatibility: Single URL functionality remains unchanged

Example Usage

// Single URL (unchanged)
lighthousePlugin('https://example.com')

// Multiple URLs
lighthousePlugin([
  'https://example.com',
  'https://example.com/about',
  'https://example.com/contact'
])

// Multiple weighted URLs
lighthousePlugin({
  'https://example.com': 3,
  'https://example.com/about': 2,
  'https://example.com/contact': 1
})

// Category merging
const plugin = lighthousePlugin(['https://example.com', 'https://example.com/about']);
const categories = mergeLighthouseCategories(plugin, userCategories);

[github-actions]

Code PushUp

🤨 Code PushUp report has both improvements and regressions – compared current commit 1e0a15d with previous commit 73c2989.

🕵️ See full comparison in Code PushUp portal 🔍

🏷️ Categories

🏷️ Category	⭐ Previous score	⭐ Current score	🔄 Score change
Performance	🟡 57	🟡 57
Code coverage	🟢 90	🟢 90
Documentation	🔴 23	🔴 23
Security	🟡 61	🟡 61	–
Updates	🟡 77	🟡 77	–
Accessibility	🟢 92	🟢 92	–
Best Practices	🟢 100	🟢 100	–
SEO	🟡 61	🟡 61	–
Type Safety	🟢 100	🟢 100	–
Bug prevention	🟢 100	🟢 100	–
Miscellaneous	🟢 100	🟢 100	–
Code style	🟢 100	🟢 100	–

👍 1 group improved, 👎 2 groups regressed, 👍 7 audits improved, 👎 5 audits regressed, 10 audits changed without impacting score

🗃️ Groups

🔌 Plugin	🗃️ Group	⭐ Previous score	⭐ Current score	🔄 Score change
Lighthouse	Performance	🟡 57	🟡 57
Code coverage	Code coverage metrics	🟢 90	🟢 90
JSDoc coverage	Documentation coverage	🔴 23	🔴 23

18 other groups are unchanged.

🛡️ Audits

🔌 Plugin	🛡️ Audit	📏 Previous value	📏 Current value	🔄 Value change
Lighthouse	Total Blocking Time	🟥 1,510 ms	🟥 1,940 ms
Lighthouse	First Contentful Paint	🟥 3.0 s	🟨 2.9 s
Lighthouse	Largest Contentful Paint	🟨 3.3 s	🟨 3.2 s
Lighthouse	Speed Index	🟨 5.2 s	🟨 5.1 s
Lighthouse	Time to Interactive	🟥 12.1 s	🟥 12.7 s
JSDoc coverage	Classes coverage	🟥 7 undocumented classes	🟥 8 undocumented classes
JSDoc coverage	Functions coverage	🟥 476 undocumented functions	🟥 494 undocumented functions
Code coverage	Branch coverage	🟨 85.7 %	🟨 86 %
Code coverage	Line coverage	🟨 86.5 %	🟨 86.8 %
Code coverage	Function coverage	🟩 93.1 %	🟩 93.3 %
JSDoc coverage	Types coverage	🟥 223 undocumented types	🟥 227 undocumented types
JSDoc coverage	Variables coverage	🟥 218 undocumented variables	🟥 221 undocumented variables
Lighthouse	Avoids enormous network payloads	🟩 Total size was 1,941 KiB	🟩 Total size was 1,945 KiB
Lighthouse	Minimizes main-thread work	🟥 10.2 s	🟥 12.1 s
Lighthouse	JavaScript execution time	🟥 4.4 s	🟥 5.5 s
Lighthouse	Metrics	🟩 100%	🟩 100%
Lighthouse	Max Potential First Input Delay	🟥 1,050 ms	🟥 1,460 ms
Lighthouse	Server Backend Latencies	🟩 230 ms	🟩 80 ms
Lighthouse	Reduce unused CSS	🟥 Potential savings of 63 KiB	🟥 Potential savings of 70 KiB
Lighthouse	Uses efficient cache policy on static assets	🟨 30 resources found	🟨 30 resources found
Lighthouse	Initial server response time was short	🟩 Root document took 430 ms	🟩 Root document took 520 ms
Lighthouse	Network Round Trip Times	🟩 20 ms	🟩 20 ms

583 other audits are unchanged.

[matejchalk]

Nice work 👍