[9480] Change QTS terminology from 'standards' to 'requirements'

[tomtrentham]

Context

Trello card

Changes proposed in this pull request

• Update QTS terminology from 'standards' to 'requirements' where feasible
• Avoid breaking changes in API
• Make error messages clearer where necessary

Guidance to review

Important business

• Does this PR introduce any PII fields that need to be overwritten or deleted in db/scripts/sanitise.sql?
• Does this PR change the database schema? If so, have you updated the config/analytics.yml file and considered whether you need to send 'import_entity' events?
• Do we need to send any updates to TRS as part of the work in this PR?
• Does this PR need an ADR?

NB: Please notify the #twd_data_insights team and ask for a review if new fields are being added to analytics.yml

[sonarqubecloud]

Quality Gate failed

Failed conditions
11.4% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.53%. Comparing base (6641ac4) to head (92470c9).
⚠️ Report is 51 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6058   +/-   ##
=======================================
  Coverage   96.53%   96.53%           
=======================================
  Files         841      841           
  Lines       18740    18747    +7     
=======================================
+ Hits        18090    18097    +7     
  Misses        650      650           

Flag	Coverage Δ
unittests	96.53% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

Review app for PR pr-6058 was deleted

[tomtrentham]

QTS terminology: standards to requirements review

[tehseenudin]

Tested all error message scenarios listed in lucid board and looks good!

Two questions about URLs which contain "recommend":

/bulk-update/recommend/4/upload-summary

/bulk-update/recommend/choose-who-to-recommend

[tomtrentham]

Remove columns from v2026.x reference data docs