refactor: single now_unix in hive_sh4re::wire_time

replaces 15 per-module copies (now_unix/now_secs) across hive-c0re and
hive-ag3nt; wire_time already owns the epoch-seconds convention

hive-sh4re/src/wire_time.rs

@@ -15,6 +15,19 @@ pub fn from_secs(secs: i64) -> DateTime<Utc> {
     DateTime::<Utc>::from_timestamp(secs, 0).unwrap_or_default()
 }
 
+/// Current unix timestamp in seconds — the single definition behind
+/// every store's `created_at` / `sent_at` / … stamp (this module owns
+/// the epoch-seconds convention; a dozen local copies of this fn used
+/// to float around both binaries). Clamps to 0 on a pre-epoch clock.
+#[must_use]
+pub fn now_unix() -> i64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .ok()
+        .and_then(|d| i64::try_from(d.as_secs()).ok())
+        .unwrap_or(0)
+}
+
 #[cfg(test)]
 mod tests {
     use chrono::{DateTime, Utc};