feat(safety): fetch reports and fetch snapshot API

crates/quark/src/traits/safety/snapshot.rs

@@ -5,4 +5,7 @@ use crate::Result;
 pub trait AbstractSnapshot: Sync + Send {
     /// Insert a new snapshot into the database
     async fn insert_snapshot(&self, snapshot: &Snapshot) -> Result<()>;
+
+    /// Fetch a snapshot by a report's id
+    async fn fetch_snapshot(&self, report_id: &str) -> Result<Snapshot>;
 }