Add download verification with signature and SHA256 support

src/core/database.rs

@@ -1757,6 +1757,14 @@ impl Database {
         Ok(())
     }
 
+    pub fn set_verification_status(&self, id: i64, status: &str) -> SqlResult<()> {
+        self.conn.execute(
+            "UPDATE appimages SET verification_status = ?2 WHERE id = ?1",
+            params![id, status],
+        )?;
+        Ok(())
+    }
+
     // --- Launch statistics ---
 
     pub fn get_top_launched(&self, limit: i32) -> SqlResult<Vec<(String, u64)>> {