StrictMetricsEvaluator does not use column bounds to evaluate startsWith

[bharos]

Feature Request / Improvement

StrictMetricsEvaluator.startsWith currently always returns ROWS_MIGHT_NOT_MATCH, ignoring file-level column bounds entirely.

When the column's lower and upper bounds prove that every value in the file starts with the given prefix, the evaluator should return ROWS_MUST_MATCH. This allows the engine to skip unnecessary row-level filtering for STARTS WITH predicates, improving query performance on string-heavy workloads.

Specifically, the evaluator can determine that all rows match STARTS WITH <prefix> when:

• The column contains no null values
• Both the lower and upper bounds start with the prefix (truncated lower/upper each equal the prefix)

This mirrors how eq and the recently added notStartsWith (#15882) already use bounds in the same evaluator.

Query engine

None

Willingness to contribute

• I can contribute this improvement/feature independently
• I would be willing to contribute this improvement/feature with guidance from the Iceberg community
• I cannot contribute this improvement/feature at this time