Course dates don't match 15-week duration (JS Front-end RU/EN)

[tarabrinjac]

❗ What is Wrong

The end dates displayed on the public course pages (e.g. "JS / Front-end RU" and "JS / Front-end EN") do not match the 15-week Stage 1 duration stated below in the text on the page of each of the courses. The site currently shows a short range (or inconsistent dates), which can confuse prospective students including me.

Where I saw it

• Course pages:
  • JS / Front-end RU,
  • JS / Front-end EN

✅ Definition of Done (DoD)

• Dates displayed on the site for Stage 1 courses are consistent with the 15-week duration (if the start date is Sep 8, 2025, the end date should be Dec 21/22, 2025, depending on inclusivity).
  • Option A: Update displayed end date to match a 15-week period (e.g. Sep 08, 2025 - Dec 21, 2025).
  • Option B: If the end date is not confirmed, omit the end date and display only the confirmed start date (or show TBD for the end).
• If the source of truth is Contentful, confirm that Contentful values are updated and the /app/courses.json (or the caching mechanism) is in sync with CMS.
• Add a short QA check (manual) that verifies both EN and RU pages show the corrected output.

Suggested fix (for maintainers / contributors)

• Verify Contentful entries for the affected courses; update the end date to reflect 15 weeks from the start (or remove the end date if unknown).
• If the site uses a cached JSON (e.g. /app/courses.json), ensure the sync job updates it after Contentful changes (or add a CI check to ensure content freshness).
• Optional: add a small note in the UI when the end date is unknown: Start: Sep 08, 2025 - End: TBD.

Evidence

• Screenshots:
  
  
• Relevant code observation: course-api.ts fetches /app/courses.json - this JSON may be stale or not updated from CMS.

Additional context

I can open a follow-up PR if maintainers prefer: either (a) small documentation change (content update guidance) or (b) a minor UI fallback to hide end date when it's not provided.

Labels suggestion: data, good first issue, help wanted