Parallelize DFS, use an AtomicBool for short-circuiting

time:   [73.407 µs 76.145 µs 79.345 µs]
change: [−40.126% −24.679% −3.8062%] (p = 0.04 < 0.05)

src-tauri/src/slot.rs

@@ -113,6 +113,16 @@ impl Default for Slot {
     }
 }
 
+impl From<u8> for Slot {
+    fn from(value: u8) -> Self {
+        let mut slot = Slot::default();
+        for _ in 0..value {
+            slot = slot.next()
+        }
+        slot
+    }
+}
+
 #[derive(Serialize, Deserialize, PartialEq, PartialOrd, Ord, Eq, Debug, Hash, Clone, Copy)]
 #[serde(rename_all = "camelCase")]
 pub struct Day(pub u8);