46e739eead
When a C# property is nullable (int?, long?, etc.), protobuf3 defaults to 0 when the field is not set. The generator now treats 0 as null for nullable numeric properties, allowing proper optional field semantics. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>