refactor: Potential fixes for 5 code quality findings in src/aes.rs

[Pr0methean]

This PR applies 5/5 suggestions from code quality AI findings.

[amazon-q-developer]

Summary

This PR applies 5 code quality improvements to src/aes.rs. Most changes are working improvements to code clarity and correctness:

✅ Working improvements:

• Simplified module path reference (line 38)
• Simplified Zeroizing type from Box<[u8]> to Vec<u8> (line 208)
• Enhanced error reporting in AesReader::validate (lines 224-228)
• Replaced assert! with debug_assert! and added explicit runtime check (lines 302-311)

⚠️ Issue found:

• Inconsistent error handling (line 387): The writer discards HMAC initialization error details while the reader includes them, making debugging inconsistent

Recommendation: Address the error handling inconsistency before merge to maintain consistent debugging capabilities across the codebase.

---

You can now have the agent implement changes and create commits directly on your pull request's source branch. Simply comment with /q followed by your request in natural language to ask the agent to make changes.

[gemini-code-assist]

Code Review

This pull request simplifies internal types by using Zeroizing<Vec> instead of boxed slices and cleans up path references. It also updates error handling for HMAC initialization and replaces a hard assertion with a runtime check for finalized states. Feedback indicates that the new check for finalized HMACs is redundant due to existing control flow logic. Additionally, a regression was identified where error details were removed from an HMAC initialization failure message, creating inconsistency with other improvements in the same PR.

[gemini-code-assist]

The debug_assert! and the subsequent if self.finalized check are redundant. Because of the early return at line 284 (if self.data_remaining == 0 { return Ok(0); }), this block is only reachable the first time self.data_remaining reaches zero during a read call. At that point, self.finalized is guaranteed to be false. Any subsequent calls to read will return at line 284 before reaching this logic.