libs/kaptan-time: add monotonic timestamp contract

libs/kaptan-time/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "kaptan-time"
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+version.workspace = true
+
+[lints]
+workspace = true

libs/kaptan-time/src/lib.rs

@@ -0,0 +1,32 @@
+//! Monotonic flight-controller time values and clock contract.
+
+#![no_std]
+
+/// Monotonic microsecond instant since boot.
+///
+/// Platform clocks must extend narrower counters before constructing this type.
+/// A value never wraps during one power cycle.
+#[derive(Clone, Copy, Debug, Default, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Timestamp(u64);
+
+impl Timestamp {
+    /// Creates an instant from monotonic microseconds since boot.
+    pub const fn from_microseconds(microseconds: u64) -> Self {
+        Self(microseconds)
+    }
+
+    /// Returns the instant in monotonic microseconds since boot.
+    pub const fn as_microseconds(self) -> u64 {
+        self.0
+    }
+}
+
+/// Supplies monotonically increasing instants to reusable runtime services.
+///
+/// Implementations may extend a hardware counter internally. `now` takes a
+/// mutable receiver so an implementation can record wrap state without hidden
+/// interior mutability or synchronization.
+pub trait MonotonicClock {
+    /// Captures the current monotonic instant since boot.
+    fn now(&mut self) -> Timestamp;
+}