HasRows, RecordsAffected, GetFieldType for OCTETS and RemoveAt(int) depart from the ADO.NET contract #1282

FirebirdClient 10.3 (Firebird 4.0 and 5.0) departs from the documented ADO.NET contract in four places. I have a pull request ready with a fix and tests for each, and I'll link it here. I'm opening this first, as CONTRIBUTING asks.

1. HasRows is true for an empty result. It returns _command.HasFields, which says whether the statement has columns, not whether it has rows.
   DbDataReader.HasRows: "true if the DbDataReader contains one or more rows; otherwise false."
2. RecordsAffected is 0 for a SELECT. _recordsAffected starts at 0, although UpdateRecordsAffected treats -1 as "no count yet", and the reader adds the statement's count whatever the statement type.
   DbDataReader.RecordsAffected: "-1 for SELECT statements; 0 if no rows were affected or the statement failed."
3. GetFieldType reports String for CHAR/VARCHAR ... CHARACTER SET OCTETS, but GetValue returns byte[] (DbField.SetValue stores octets as bytes).
   IDataRecord.GetFieldType: "the type of Object that would be returned from GetValue."
4. FbParameterCollection.RemoveAt(int) throws IndexOutOfRangeException for an invalid index. The range check is also off by one (index > Count), so RemoveAt(Count) fails later, in the indexer.
   DbParameterCollection.RemoveAt(Int32) implements IList.RemoveAt: ArgumentOutOfRangeException when "index is not a valid index in the IList."

Found by the pengdows ADO.NET conformance suite: HasRows_returns_false_when_no_rows, RecordsAffected_returns_negative_1_after_close_when_no_rows, GetFieldType_matches_GetValue_for_supported_values, ParameterCollection_RemoveAt_negative_one_throws.

AI disclosure: the analysis, the fix and this text were produced with Claude Code (an AI assistant).