Fix ESLint warnings and errors

- Remove unused imports in test files
- Fix unused variable warnings
- Fix React unescaped entity warning in settings page
- Remove unused error parameters in catch blocks

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/obsClient.js

@@ -380,7 +380,7 @@ async function createStreamGroup(groupName, streamName, teamName, url, lockSourc
     try {
       await obsClient.call('CreateScene', { sceneName: streamGroupName });
       console.log(`Created nested scene "${streamGroupName}" for stream grouping`);
-    } catch (error) {
+    } catch {
       console.log(`Nested scene "${streamGroupName}" might already exist`);
     }
     
@@ -535,7 +535,7 @@ async function createStreamGroup(groupName, streamName, teamName, url, lockSourc
           console.error(`Failed to lock color source:`, lockError.message);
         }
       }
-    } catch (error) {
+    } catch {
       console.log('Color source background might already be in nested scene');
     }
     
@@ -559,7 +559,7 @@ async function createStreamGroup(groupName, streamName, teamName, url, lockSourc
           console.error(`Failed to lock text source:`, lockError.message);
         }
       }
-    } catch (error) {
+    } catch {
       console.log('Text source might already be in nested scene');
     }