[ISSUE #2889] Deduplicate LiteTopic TTL extensions

[yuluo-yx]

What changed\n\n- acquire a synchronous in-flight guard before extending a LiteTopic TTL\n- release the guard on success or failure\n- add a deferred-promise regression for two confirmations in the same render\n\n## Why\n\nThe modal loading state alone did not prevent duplicate write requests before React committed the disabled state.\n\n## Verification\n\n- npm test -- --run src/pages/studio/tests/LiteTopic.test.tsx\n- Prettier and ESLint on the two changed files (existing Fast Refresh warning only)\n- scope check: 2 files, 23 changed lines\n\nFixes #2889

[RockteMQ-AI]

Summary

[ISSUE #2889] Deduplicate LiteTopic TTL extensions

Clean fix with proper deduplication guard and regression test coverage. No blocking issues.

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Automated review by github-manager-bot

[lizhimins]

Closing after review: extending a LiteTopic TTL is an idempotent operation — a double-click merely repeats the same extension with no harmful side effect, so the in-flight guard here addresses a scenario that cannot cause real damage. To keep the mainline free of low-value changes we're passing on this one; the other in-flight guard PRs covering genuinely duplicable mutations were merged in the batch integration. Thanks for the contribution!