fix: resolve intermittent auth errors when navigating between tabs

Token refresh race condition: when multiple requests got 401 simultaneously,
queued retries reused stale headers and the initiator fell through without
throwing on retry failure. Now retries regenerate headers (fresh request ID
and CSRF token), and both retry failure and refresh failure throw explicitly.

SWR cache is now invalidated after token refresh so stale error responses
are not served from cache.

lib/auth/context.tsx

@@ -2,6 +2,7 @@
 
 import React, { createContext, useContext, useEffect, useState, useCallback } from 'react'
 import { useRouter, usePathname } from 'next/navigation'
+import { useSWRConfig } from 'swr'
 import apiRequest from '@/lib/api/client'
 import { LoadingOverlay, useSessionSync, SessionExpiryWarning } from '@ciphera-net/ui'
 import { logoutAction, getSessionAction, setSessionAction } from '@/app/actions/auth'
@@ -51,6 +52,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
   const [isLoggingOut, setIsLoggingOut] = useState(false)
   const router = useRouter()
   const pathname = usePathname()
+  const { mutate: swrMutate } = useSWRConfig()
 
   const refreshToken = useCallback(async (): Promise<boolean> => {
     try {
@@ -109,7 +111,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
   const refresh = useCallback(async () => {
     try {
       const userData = await apiRequest<User>('/auth/user/me')
-      
+
       setUser(prev => {
         const merged = {
           ...userData,
@@ -122,8 +124,10 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
     } catch (e) {
       logger.error('Failed to refresh user data', e)
     }
+    // * Clear SWR cache so stale data isn't served after token refresh
+    swrMutate(() => true, undefined, { revalidate: true })
     router.refresh()
-  }, [router])
+  }, [router, swrMutate])
 
   const refreshSession = useCallback(async () => {
       await refresh()