fix: Resolve all ESLint errors and warnings in web package

Fixes all 542 ESLint problems in the web package to achieve 0 errors and 0 warnings.

Changes:
- Fixed 144 issues: nullish coalescing, return types, unused variables
- Fixed 118 issues: unnecessary conditions, type safety, template literals
- Fixed 79 issues: non-null assertions, unsafe assignments, empty functions
- Fixed 67 issues: explicit return types, promise handling, enum comparisons
- Fixed 45 final warnings: missing return types, optional chains
- Fixed 25 typecheck-related issues: async/await, type assertions, formatting
- Fixed JSX.Element namespace errors across 90+ files

All Quality Rails violations resolved. Lint and typecheck both pass with 0 problems.

Files modified: 118 components, tests, hooks, and utilities

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

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

@@ -27,13 +27,13 @@ export function TeamMemberList({
   onAddMember,
   onRemoveMember,
   availableUsers = [],
-}: TeamMemberListProps) {
+}: TeamMemberListProps): React.JSX.Element {
   const [isAdding, setIsAdding] = useState(false);
   const [selectedUserId, setSelectedUserId] = useState("");
   const [selectedRole, setSelectedRole] = useState(TeamMemberRole.MEMBER);
   const [removingUserId, setRemovingUserId] = useState<string | null>(null);
 
-  const handleAddMember = async () => {
+  const handleAddMember = async (): Promise<void> => {
     if (!selectedUserId) return;
 
     setIsAdding(true);
@@ -49,7 +49,7 @@ export function TeamMemberList({
     }
   };
 
-  const handleRemoveMember = async (userId: string) => {
+  const handleRemoveMember = async (userId: string): Promise<void> => {
     setRemovingUserId(userId);
     try {
       await onRemoveMember(userId);