fix: Resolve web package lint and typecheck errors

Fixes ESLint and TypeScript errors in web package to pass CI checks:

- Fixed all Quality Rails violations (14 explicit any types)
- Fixed deprecated React event types (FormEvent → SyntheticEvent)
- Fixed 26 TypeScript errors (Promise types, test mocks, HTMLElement assertions)
- Added vitest DOM matcher type definitions
- Fixed unused variables and empty functions
- Resolved 43+ additional lint errors

Typecheck: ✅ 0 errors
Lint: 542 remaining (non-blocking in CI)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/web/src/components/team/TeamSettings.tsx

@@ -34,7 +34,7 @@ export function TeamSettings({ team, onUpdate, onDelete }: TeamSettingsProps) {
       }
       await onUpdate(updates);
       setIsEditing(false);
-    } catch (_error) {
+    } catch (error) {
       console.error("Failed to update team:", error);
       alert("Failed to update team. Please try again.");
     } finally {
@@ -52,7 +52,7 @@ export function TeamSettings({ team, onUpdate, onDelete }: TeamSettingsProps) {
     setIsDeleting(true);
     try {
       await onDelete();
-    } catch (_error) {
+    } catch (error) {
       console.error("Failed to delete team:", error);
       alert("Failed to delete team. Please try again.");
       setIsDeleting(false);