fix: validate ATA derivation in both idempotent and non-idempotent paths

[ananas-block]

Summary

• Move ATA derivation validation before the idempotent early-return check so it runs in both code paths, preventing creation of non-derived ATA accounts.

[coderabbitai]

📝 Walkthrough

Walkthrough

The ATA derivation validation logic is refactored to perform validation uniformly in both idempotent and non-idempotent modes, then optimize the idempotent path by combining the early-return condition into a single check when the ATA is owned by LIGHT_CPI_SIGNER.

Changes

Cohort / File(s)	Summary
ATA Derivation Validation Optimization programs/compressed-token/program/src/ctoken/create_ata.rs	Reorganized validation logic to perform ATA derivation validation upfront for all modes, then combine the idempotent early-return condition into a single check, eliminating redundant re-validation when ATA is owned by LIGHT_CPI_SIGNER.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested labels

ai-review

Suggested reviewers

• sergeytimoshin
• SwenSchaeferjohann

Poem

✨ Validations dance in perfect stride,
Early returns, no double-check tide,
ATA signer's ownership claims its place,
One unified path—efficiency embraced! 🚀

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly and accurately describes the main change: moving ATA derivation validation to run in both code paths before the idempotent early return.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 70.00%.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/audit-issue-3-ata-derivation-check

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[ananas-block]

Superseded by #2249 which combines issues #3, #4, and #15.