Throw storage error when lock aquire fails

[icellan]

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[github-actions]

🤖 Claude Code Review

Status: Complete

Summary

This PR corrects the error type for write permit acquisition failures from NewProcessingError to NewStorageError. This aligns with how other file storage operations handle errors throughout the same file.

Issue Found

There is an inconsistency between read and write permit error handling:

• Line 280 (acquireReadPermit): Uses NewProcessingError for semaphore acquisition failures
• Line 303 (acquireWritePermit): Now uses NewStorageError (after this PR)

Both functions handle semaphore acquisition for the same purpose (controlling filesystem access), so they should use the same error type. Since all other file storage operations in this file use NewStorageError, the read permit function should also be updated for consistency.

Recommendation

Consider updating line 280 in a follow-up PR to use NewStorageError instead of NewProcessingError to maintain consistency across both semaphore acquisition functions.