feat: print solution on start

src/challenge/c1.rs

@@ -18,6 +18,7 @@ impl C1 {}
 #[async_trait]
 impl Challenge for C1 {
     fn new(config: Config, vault: VaultRef) -> Self {
+        info!("Solution: {}", Self::solution());
         Self { config, vault }
     }
 

src/challenge/c2.rs

@@ -36,6 +36,7 @@ impl C2 {
 #[async_trait]
 impl Challenge for C2 {
     fn new(config: Config, vault: VaultRef) -> Self {
+        info!("Solution: {}", Self::solution());
         Self { config, vault }
     }