🧹 [code health improvement] Resolve unnecessary clone in database module

[Tcode-Motion]

🎯 What: Analyzed a "potential unnecessary clone" warning in stdlib/src/database.rs and resolved it by replacing IndexMap::new() with IndexMap::with_capacity(column_names.len()). Also added documentation confirming that name.clone() is strictly necessary because IndexMap requires an owned String key for each row.
💡 Why: Pre-allocating the map capacity prevents reallocation overhead during row insertion, improving performance. The comment improves code maintainability by explaining the false-positive warning.
✅ Verification: Ran the full test suite (cargo test --workspace) and clippy (cargo clippy --workspace --all-targets -- -D warnings), confirming no regressions.
✨ Result: A verified code health improvement with a minor performance win, while avoiding performance regressions associated with attempting to dynamically fetch column names.

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PR created automatically by Jules for task 18090797020747901647 started by @Tcode-Motion

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