The correctness baseline

Implement search by scanning every item. It receives vector, k, metric, and an optional filter. Keep items whose metadata contains every requested key-value pair using JSON equality.

Sort by ascending distance and then lexicographic id. Return at most k objects containing only id and distance. Reuse six-decimal rounding.

This O(n) search becomes the oracle for evaluating the approximate index: optimize only after establishing a correct baseline.

• k must be a positive integer.
• Ties are deterministic.
• Filter before sorting and limiting.