fix(frontend): Fix critical type safety issues from code review

Address all Critical and High Priority issues identified in frontend code review report:

Critical Issues Fixed:
- Created unified logger utility (lib/utils/logger.ts) to replace all console.log statements
- Consolidated User type definitions - removed duplicate from authStore, using single source from types/user.ts
- Eliminated 'any' types in API client - added proper generic types with AxiosRequestConfig
- Fixed SignalR ConnectionManager - replaced 'any' with generic types <T>
- Created API error types (lib/types/errors.ts) with ApiError and getErrorMessage helper
- Fixed IssueCard component - removed all type assertions, created discriminated union types for Kanban items
- Added React.memo to IssueCard for performance optimization
- Added proper ARIA labels and accessibility attributes to IssueCard

High Priority Issues Fixed:
- Fixed hardcoded user ID in CreateProjectDialog - now uses actual user from authStore
- Added useCallback to CreateProjectDialog onSubmit handler
- Fixed error handlers in use-epics.ts - replaced 'any' with ApiError type
- Updated all error handling to use logger and getErrorMessage

Type Safety Improvements:
- Created KanbanItem discriminated union (KanbanEpic | KanbanStory | KanbanTask) with proper type guards
- Added 'never' types to prevent invalid property access
- Fixed User interface to include all required fields (createdAt, updatedAt)
- Maintained backward compatibility with LegacyKanbanBoard for existing code

Files Changed:
- lib/utils/logger.ts - New centralized logging utility
- lib/types/errors.ts - New API error types and helpers
- types/user.ts - Consolidated User type with TenantRole
- types/kanban.ts - New discriminated union types for type-safe Kanban items
- components/features/kanban/IssueCard.tsx - Type-safe with React.memo
- components/features/projects/CreateProjectDialog.tsx - Fixed hardcoded user ID, added useCallback
- lib/api/client.ts - Eliminated 'any', added proper generics
- lib/signalr/ConnectionManager.ts - Replaced console.log, added generics
- lib/hooks/use-epics.ts - Fixed error handler types
- stores/authStore.ts - Removed duplicate User type
- lib/hooks/useAuth.ts - Added createdAt field to User

TypeScript compilation: ✅ All type checks passing (0 errors)

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

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

types/kanban.ts

@@ -1,5 +1,96 @@
-import { Task, TaskStatus } from './project';
+/**
+ * Kanban-specific types with discriminated unions
+ * Ensures type safety for Epic, Story, and Task cards
+ */
 
+import { WorkItemStatus, WorkItemPriority } from './project';
+
+// Base Kanban item interface with common properties
+interface BaseKanbanItem {
+  id: string;
+  projectId: string;
+  status: WorkItemStatus;
+  priority: WorkItemPriority;
+  description?: string;
+  estimatedHours?: number;
+  actualHours?: number;
+  assigneeId?: string;
+  tenantId: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+// Epic as Kanban item - discriminated by 'type' field
+export interface KanbanEpic extends BaseKanbanItem {
+  type: 'Epic';
+  name: string;  // Epic uses 'name' instead of 'title'
+  createdBy: string;
+  childCount?: number;  // Number of stories in this epic
+  epicId?: never;  // Epic doesn't have epicId
+  storyId?: never;  // Epic doesn't have storyId
+  title?: never;  // Epic uses 'name', not 'title'
+}
+
+// Story as Kanban item - discriminated by 'type' field
+export interface KanbanStory extends BaseKanbanItem {
+  type: 'Story';
+  title: string;  // Story uses 'title'
+  epicId: string;  // Story always has epicId
+  childCount?: number;  // Number of tasks in this story
+  storyId?: never;  // Story doesn't have storyId
+  name?: never;  // Story uses 'title', not 'name'
+}
+
+// Task as Kanban item - discriminated by 'type' field
+export interface KanbanTask extends BaseKanbanItem {
+  type: 'Task';
+  title: string;  // Task uses 'title'
+  storyId: string;  // Task always has storyId
+  epicId?: never;  // Task doesn't have epicId (only through story)
+  childCount?: never;  // Task doesn't have children
+  name?: never;  // Task uses 'title', not 'name'
+}
+
+// Discriminated union type for Kanban items
+// TypeScript can narrow the type based on the 'type' field
+export type KanbanItem = KanbanEpic | KanbanStory | KanbanTask;
+
+// Type guards for runtime type checking
+export function isKanbanEpic(item: KanbanItem): item is KanbanEpic {
+  return item.type === 'Epic';
+}
+
+export function isKanbanStory(item: KanbanItem): item is KanbanStory {
+  return item.type === 'Story';
+}
+
+export function isKanbanTask(item: KanbanItem): item is KanbanTask {
+  return item.type === 'Task';
+}
+
+// Helper to get display title regardless of type
+export function getKanbanItemTitle(item: KanbanItem): string {
+  if (isKanbanEpic(item)) {
+    return item.name;
+  }
+  return item.title;
+}
+
+// Kanban column type
+export interface KanbanColumn {
+  id: WorkItemStatus;
+  title: string;
+  items: KanbanItem[];
+}
+
+// Kanban board type
+export interface KanbanBoard {
+  projectId: string;
+  projectName: string;
+  columns: KanbanColumn[];
+}
+
+// ==================== Legacy Types (for backward compatibility) ====================
 export interface TaskCard {
   id: string;
   title: string;
@@ -10,14 +101,16 @@ export interface TaskCard {
   actualHours?: number;
 }
 
-export interface KanbanColumn {
-  status: TaskStatus;
+// Legacy KanbanColumn type for backward compatibility
+export interface LegacyKanbanColumn {
+  status: string;
   title: string;
   tasks: TaskCard[];
 }
 
-export interface KanbanBoard {
+// Legacy KanbanBoard type
+export interface LegacyKanbanBoard {
   projectId: string;
   projectName: string;
-  columns: KanbanColumn[];
+  columns: LegacyKanbanColumn[];
 }