negative buffer size handling in ODBCAppender to prevent unsigned overflow

[jmestwa-coder]

Summary

Fixes an issue where negative values provided to the BUFFERSIZE option in ODBCAppender could be cast to an unsigned type, resulting in an unintended very large buffer size.

Problem

• OptionConverter::toInt() may return negative values (for example "-10").`
• These values were directly cast to size_t, causing negative values to become large positive numbers.

Fix

Adds a simple guard before casting to ensure negative values are not converted to unsigned:

int parsed = OptionConverter::toInt(value, 1);
if (parsed < 0) {
    parsed = 1;
}
setBufferSize((size_t) parsed);

Behaviour Impact

• No change for valid inputs.
• Only negative values are corrected.
• Existing parsing behaviour remains unchanged.

Tests

Added testNegativeBufferSizeOption to verify negative values fallback to 1.

Scope

• Limited to ODBCAppender::setOption (BUFFERSIZE path).
• No changes to parsing logic or shared utilities.