Improve Codeforces Problem Workspace editor UX

[Copilot]

Summary

• upgraded the Codeforces Problem Workspace editor experience to feel Kotlin-native while staying focused on editing-only scope
• kept the workspace structure intact: statement on the left, editor on the right, and samples/test-results panel below the editor
• added quality-of-life UX around drafts and editor context without adding execution/submission/auth features

Changes

• improved the existing textarea editor behavior and presentation:
  • Kotlin-focused header (Kotlin, .kt) and monospace coding experience
  • custom Tab handling to insert spaces instead of moving focus
  • stronger coding-surface styling for the editor panel
• preserved draft persistence semantics and per-problem storage key:
  • draft key remains hdd-codeforces-draft-{contestId}-{index}
  • localStorage persistence still saves per-problem drafts
• added default Kotlin starter code when no draft exists:
  • fun main() {
  • // solve here
  • }
• updated editor actions area to keep placeholders visible while inactive:
  • Run Samples remains visible and disabled
  • Prepare Submit remains visible and disabled
• added Reset Draft with explicit confirmation (active)
• added post-edit local persistence feedback via Saved locally status
• added problem id near the editor header for quick context
• kept Codeforces original link visually small/secondary

Validation

• npm test ✅
• npm run lint ✅
• npm run build ✅

Notes

• No code execution was added
• No direct Codeforces submission was added
• No login/auth was added
• No Kotlin library injection was added
• No unrelated page refactors were introduced

[enlorik]

Tiny follow-up on this PR before merge.

In ProblemWorkspace.jsx, keep the existing placeholder buttons visible:

• Run Samples
• Prepare Submit

They should remain disabled for now because this PR must not add execution or submission.

Keep the new Reset Draft button too.

Desired editor actions area:

• Saved locally status when edited
• Run Samples disabled
• Prepare Submit disabled
• Reset Draft active

Do not add code execution.
Do not add submission.
Do not refactor unrelated files.
Run npm test, npm run lint, npm run build.

[enlorik]

Copilot, please apply this small requested change directly to this PR.

In ProblemWorkspace.jsx, restore the existing placeholder buttons in the editor actions area:

• Run Samples disabled
• Prepare Submit disabled

Keep the new Reset Draft button active.
Keep the Saved locally status when edited.

Desired editor actions area:

• Saved locally status when edited
• Run Samples disabled
• Prepare Submit disabled
• Reset Draft active

Do not add code execution.
Do not add submission.
Do not refactor unrelated files.
Keep this PR scoped to the editor UX.

After changing it, run:

• npm test
• npm run lint
• npm run build

[enlorik]

@copilot please apply this small requested change directly to this PR.

In ProblemWorkspace.jsx, restore the existing placeholder buttons in the editor actions area:

• Run Samples disabled
• Prepare Submit disabled

Keep the new Reset Draft button active.
Keep the Saved locally status when edited.

Desired editor actions area:

• Saved locally status when edited
• Run Samples disabled
• Prepare Submit disabled
• Reset Draft active

Do not add code execution.
Do not add submission.
Do not refactor unrelated files.
Keep this PR scoped to the editor UX.

After changing it, run:

• npm test
• npm run lint
• npm run build

[Copilot]

@copilot please apply this small requested change directly to this PR.

In ProblemWorkspace.jsx, restore the existing placeholder buttons in the editor actions area:...

Implemented in commit 2b3507c.

I restored the disabled placeholder buttons in the editor actions area (Run Samples, Prepare Submit), kept Reset Draft active, and kept Saved locally shown after edits.

Validation passed:

• npm test
• npm run lint
• npm run build