feat(detmir): add rust-first operations tooling

adk-rust/crates/detmir-core/src/lib.rs

@@ -0,0 +1,88 @@
+use std::fmt;
+
+use anyhow::{Context, Result};
+use chrono::{DateTime, SecondsFormat, Utc};
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "UPPERCASE")]
+pub enum StatusLevel {
+    Ok,
+    Warn,
+    Fail,
+    Unknown,
+}
+
+impl StatusLevel {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::Ok => "OK",
+            Self::Warn => "WARN",
+            Self::Fail => "FAIL",
+            Self::Unknown => "UNKNOWN",
+        }
+    }
+
+    pub fn exit_code(self) -> i32 {
+        match self {
+            Self::Ok => exit_codes::OK,
+            Self::Warn | Self::Fail | Self::Unknown => exit_codes::CHECK_FAILED,
+        }
+    }
+}
+
+impl fmt::Display for StatusLevel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl From<&str> for StatusLevel {
+    fn from(value: &str) -> Self {
+        match value.trim().to_ascii_uppercase().as_str() {
+            "OK" => Self::Ok,
+            "WARN" | "WARNING" => Self::Warn,
+            "FAIL" | "FAILED" | "ERROR" => Self::Fail,
+            _ => Self::Unknown,
+        }
+    }
+}
+
+pub mod exit_codes {
+    pub const OK: i32 = 0;
+    pub const ERROR: i32 = 1;
+    pub const CHECK_FAILED: i32 = 2;
+    pub const POLICY_DENIED: i32 = 3;
+}
+
+pub fn now_utc_rfc3339() -> String {
+    Utc::now().to_rfc3339_opts(SecondsFormat::Secs, true)
+}
+
+pub fn parse_utc_rfc3339(value: &str) -> Result<DateTime<Utc>> {
+    DateTime::parse_from_rfc3339(value)
+        .with_context(|| format!("invalid RFC3339 timestamp: {value}"))
+        .map(|ts| ts.with_timezone(&Utc))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn status_level_maps_known_values() {
+        assert_eq!(StatusLevel::from("OK"), StatusLevel::Ok);
+        assert_eq!(StatusLevel::from("warn"), StatusLevel::Warn);
+        assert_eq!(StatusLevel::from("ERROR"), StatusLevel::Fail);
+        assert_eq!(StatusLevel::from("other"), StatusLevel::Unknown);
+    }
+
+    #[test]
+    fn parses_zulu_timestamp() {
+        let ts = parse_utc_rfc3339("2026-05-31T10:20:30Z").unwrap();
+        assert_eq!(
+            ts.to_rfc3339_opts(SecondsFormat::Secs, true),
+            "2026-05-31T10:20:30Z"
+        );
+    }
+}