fix(logging): log errors instead of silently discarding with .ok()

Replace silent .ok() calls with explicit match + warn! logging in
encode_quick_notes and passkey deserialization for exclude lists.

src/infrastructure/repositories/brews.rs

@@ -68,7 +68,13 @@ impl SqlBrewRepository {
             None
         } else {
             let labels: Vec<&str> = notes.iter().map(|n| n.label()).collect();
-            serde_json::to_string(&labels).ok()
+            match serde_json::to_string(&labels) {
+                Ok(json) => Some(json),
+                Err(err) => {
+                    tracing::warn!(error = %err, "failed to encode quick notes as JSON");
+                    None
+                }
+            }
         }
     }