Replace moment.js with day.js for smaller bundle size

[GaryJones]

Summary

Replace moment.js with day.js to reduce JavaScript bundle size. moment.js is deprecated and significantly larger than modern alternatives.

Why

Library	Size (minified + gzip)	Status
moment.js	~67 KB	Deprecated, in maintenance mode
day.js	~2 KB	Active development, similar API

Bundle impact: ~65 KB reduction (moment.js is currently in the vendor chunk)

Current Usage

// src/react/utils/extendedMoment.js
import moment from 'moment';
const date = moment(timestamp).fromNow();

Used for:

• Relative timestamps ("5 minutes ago")
• Date formatting in entries
• Locale-aware date display

Migration Path

// After
import dayjs from 'dayjs';
import relativeTime from 'dayjs/plugin/relativeTime';
dayjs.extend(relativeTime);

const date = dayjs(timestamp).fromNow();

Potential Issues

1. Locale handling - day.js loads locales separately (good for bundle size, but needs explicit import)
2. Plugin system - Some moment features require day.js plugins:
   • relativeTime - for .fromNow()
   • localizedFormat - for locale-aware formatting
   • utc - for UTC operations (if used)
3. API differences - Minor, but need to verify all usages:
   • Both use .format(), .fromNow(), .diff()
   • day.js is immutable by default (moment mutates)

Tasks

• Audit all moment.js usage in codebase
• Install day.js: npm install dayjs
• Update src/react/utils/extendedMoment.js
• Test all date displays across locales
• Remove moment.js: npm uninstall moment
• Verify bundle size reduction

References

• day.js documentation
• moment.js deprecation notice
• Migration guide