Proposal: an integer-nanosecond time type in Brutal.Core/Types

[bubbysitch]

Hello!! I'm pretty new around here so I hope this being my first post isn't bad! I came from the repo. I'm thinking of putting together a PR for a nanosecond time/duration type and wanted to see if its worth it

The plan is a readonly record struct backed by a 64-bit signed integer, living in Brutal.Core/Types/ right alongside ByteSize and ElementCount. It'd follow the exact same pattern: a single Value, explicit conversions, and checked on narrowing

Why add this?
The KSA changelog mentions moving toward integer nanosecond time for universe time, plus a 64-bit BubbleTime for physics steps. Having a dedicated type in Core gives the whole shebang one shared representation instead of passing raw longs or doubles across boundaries. (plus a double starts losing single-nanosecond precision after 2^53 ns

What the API would look like:

• FromSeconds(double) with a clear rounding rule
• ToSeconds() with a documented error bound
• Basic math & comparison: +, -, unary -, ordering, plus checked add and negate
• Constants: Zero, MinValue, MaxValue

Tests I'd include:

• FromSeconds midpoint rounding behavior
• ToSeconds round-trip accuracy and where it drifts past 1 ns (since double spacing passes 1 ns at 2^23 seconds, or ~97 days)
• Checked overflow on addition and negating MinValue
• Ordering with negative durations
• Rejecting NaN and infinity

Questions:3
1. Does Brutal.Core/Types feel like the right pklace for this?
2. Is there an existing testing framework?
3. Is a straight nanosecond long fine, or rather make it generic over the time unit?

Should be zero new dependencies! I use cloud AI agents as well! I review the output and do the best I can to show my work through excessively (I mean it) rigorous conformance. Nice to meet you all!<3

harriett