docs: add missing #[must_use], # Errors, # Panics across public api

hive-ag3nt/src/turn_stats.rs

@@ -148,6 +148,10 @@ impl TurnStats {
 
     /// Insert a row. Best-effort — logs + swallows errors so a sqlite
     /// hiccup (locked db, full disk) doesn't crash the harness.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the internal lock is poisoned.
     pub fn record(&self, row: &TurnStatRow) {
         let conn = self.inner.lock().unwrap();
         let res = conn.execute(
@@ -209,6 +213,9 @@ impl TurnStats {
     /// have last-inference zeros — those rows yield `ctx = None` so the
     /// badge stays empty until the next real turn rather than showing a
     /// misleading 0.
+    /// # Panics
+    ///
+    /// Panics if the internal lock is poisoned.
     #[must_use]
     pub fn last_usage(
         &self,