fix(python): preserve API state on failed operations

[huanglune]

Summary

• Avoid shared default IndexParams state between independently created Index() instances.
• Keep Index and Collection retryable after failed first-fit / first-insert paths instead of leaving half-initialized Python API state behind.
• Validate Client disk-delete preconditions before mutating in-memory maps, and normalize Index.insert() list inputs through the same numpy path as search APIs.
• Add focused regression coverage for each fixed API state edge case.

Test plan

• git diff --check
• timeout 60s .venv/bin/pytest -q
• timeout 60s .venv/bin/ruff check python scripts tools
• pre-commit hooks during git commit

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[codecov]

Codecov Report

❌ Patch coverage is 91.30435% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
python/src/alayalite/index.py	89.74%	3 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[gemini-code-assist]

Code Review

This pull request improves error handling and state consistency in alayalite. Specifically, it ensures that delete_collection and delete_index validate disk operations before modifying the client's internal maps, avoids using mutable default arguments in Index.init, and ensures that failed fit operations do not leave the index or collection in a corrupted state. The review feedback highlights an issue where a failed fit operation can leave orphaned RocksDB files on disk, and suggests explicitly cleaning up the rocksdb_path directory and handling exceptions during database closure to prevent masking the original error.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.