Field Value Suggestions in the Kibana ES|QL Editor

## Value Proposition

Users writing ES|QL queries must remember or manually search for specific field values when constructing WHERE clauses. This slows query authoring and leads to errors with complex or case-sensitive values.

## Expected Outcome

The Kibana ES|QL editor suggests existing field values from the index in real-time as users type — for example, after typing `| WHERE machine.os == "`, the autocomplete menu displays common values for that field.