fix(markdown): restore ratatui bold assertions

Acceptance-Criteria:
- cargo test -p owlen-markdown completes without Style::contains usage
- Workspace lint hook passes under cargo clippy --all-features -D warnings
- Markdown heading and inline code tests still confirm bold styling

Test-Notes:
- cargo test -p owlen-markdown
- cargo clippy -p owlen-markdown --tests -- -D warnings
- cargo clippy --all-features -- -D warnings

crates/owlen-core/src/session.rs

@@ -912,30 +912,24 @@ impl SessionController {
             let guard = self.config.lock().await;
             guard
                 .providers
-                .iter()
-                .map(|(name, _)| (name.clone(), Self::quota_from_config(&guard, name)))
+                .keys()
+                .map(|name| (name.clone(), Self::quota_from_config(&guard, name)))
                 .collect::<HashMap<_, _>>()
         };
 
         let now = SystemTime::now();
         let mut provider_names: HashSet<String> = quota_map.keys().cloned().collect();
 
-        let snapshots = {
-            let ledger = self.usage_ledger.lock().await;
-            for key in ledger.provider_keys() {
-                provider_names.insert(key.clone());
-            }
+        let ledger = self.usage_ledger.lock().await;
+        provider_names.extend(ledger.provider_keys().cloned());
 
-            provider_names
-                .into_iter()
-                .map(|provider| {
-                    let quota = quota_map.get(&provider).cloned().unwrap_or_default();
-                    ledger.snapshot(&provider, quota, now)
-                })
-                .collect::<Vec<_>>()
-        };
-
-        snapshots
+        provider_names
+            .into_iter()
+            .map(|provider| {
+                let quota = quota_map.get(&provider).cloned().unwrap_or_default();
+                ledger.snapshot(&provider, quota, now)
+            })
+            .collect()
     }
 
     // Asynchronous access to the configuration (used internally).