fix(i18n): replace manual pluralize() with i18next count-based plurals

[max-datahub]

Summary

Several files that are already in the i18n allowlist still call the manual
pluralization helpers (pluralize / forcePluralize / pluralizeIfIrregular)
from @app/shared/textUtil. Those helpers hardcode English plural rules (a
naive +s suffix plus a small English-only irregular map), so the text they
produce can never be localized correctly — other locales have different plural
categories and word forms.

This PR:

1. Migrates each call site to i18next's native count-based plural keys
   (_one / _other) or simple interpolation, so each locale owns its own
   plural forms, and removes the now-unused textUtil imports.
2. Adds an ESLint rule, no-manual-pluralize-in-i18n (scoped via
   .eslintrc.js to the i18n allowlist), so these helpers can't be
   reintroduced into translated files going forward.

EN-only (no DE) per the i18n extraction convention.

Keys added

• entity.types: shared.assetTypeNameCount
• entity.shared.containers: sidebar.entityTypeCount, sidebar.ownership.type.pluralName
• ingestion: source.entityTypeNameCount
• search: matches.matchedField.fieldLabelCount, filters.pluralizedTypeLabel

Files migrated

• entityV2/application/AssetsSections.tsx, entityV2/dataProduct/AssetsSections.tsx,
  entityV2/domain/summary/ContentsSection.tsx — entity-count card tooltips
• entityV2/shared/containers/profile/sidebar/{Container,Domain,Lineage}/utils.tsx —
  "{count} {type}" sidebar summaries
• entityV2/shared/containers/profile/sidebar/Ownership/ownershipUtils.ts —
  ownership-type fallback label
• ingestV2/source/utils.ts — ingestion source facet display name
• searchV2/matches/MatchedFieldList.tsx — matched-field label
• searchV2/filters/utils.tsx — filter option labels (entity type / subtype)

Pages to verify

• An Application profile → Assets section (hover an entity-count card; tooltip shows the type name)
• A Data Product profile → Assets section (entity-count card tooltips)
• A Domain profile → Contents section (entity-count card tooltips)
• Any entity profile right sidebar → Contents (container), Lineage summary, and Owners (ownership type label)
• Ingestion → Sources list (entity-type facet counts)
• Search → search filters (entity type / subtype filter option labels) and matched-field result rows

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly the Commit Message Format)
• Verified locally: ESLint (incl. the new rule), tsc --noEmit, and Prettier pass
• Links to related issues (N/A)
• Docs added/updated (N/A — internal refactor, no user-facing doc change)

🤖 Generated with Claude Code

[alwaysmeticulous]

🔴 Meticulous spotted visual differences in 16 of 1423 screens tested: view and approve differences detected.

Meticulous evaluated ~10 hours of user flows against your PR.

_{Last updated for commit e19964a chore(i18n): enforce no-manual-pluralize-in-i18n and migrate remaining c.... This comment will update as new commits are pushed.}

[codecov]

Bundle Report

Changes will increase total bundle size by 1.0kB (0.0%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
datahub-react-web-esm	23.54MB	1.0kB (0.0%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: datahub-react-web-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
assets/index-*.js	513 bytes	8.86MB	0.01%
assets/en-*.js	488 bytes	225.1kB	0.22%

Files in assets/index-*.js:

• ./src/app/entityV2/application/AssetsSections.tsx → Total Size: 2.54kB

• ./src/app/entityV2/dataProduct/AssetsSections.tsx → Total Size: 2.38kB

• ./src/app/entityV2/domain/summary/ContentsSection.tsx → Total Size: 2.67kB

• ./src/app/searchV2/matches/MatchedFieldList.tsx → Total Size: 3.33kB

• ./src/app/entityV2/shared/containers/profile/sidebar/Ownership/ownershipUtils.ts → Total Size: 1.68kB

• ./src/app/entityV2/shared/containers/profile/sidebar/Domain/utils.tsx → Total Size: 3.74kB

• ./src/app/entityV2/shared/containers/profile/sidebar/Lineage/utils.tsx → Total Size: 3.05kB

• ./src/app/entityV2/shared/containers/profile/sidebar/Container/utils.tsx → Total Size: 3.02kB

• ./src/app/searchV2/filters/utils.tsx → Total Size: 16.79kB

• ./src/app/ingestV2/source/utils.ts → Total Size: 15.7kB

Files in assets/en-*.js:

• ./src/i18n/locales/en/entity.shared.containers.json → Total Size: 14.15kB

• ./src/i18n/locales/en/ingestion.json → Total Size: 9.52kB

• ./src/i18n/locales/en/entity.types.json → Total Size: 16.22kB

• ./src/i18n/locales/en/search.json → Total Size: 8.22kB

[codecov]

Codecov Report

❌ Patch coverage is 22.22222% with 7 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
datahub-web-react/src/app/ingestV2/source/utils.ts	20.00%	4 Missing ⚠️
...ainers/profile/sidebar/Ownership/ownershipUtils.ts	25.00%	3 Missing ⚠️

📢 Thoughts on this report? Let us know!