feat: Discord links, translation sync, iOS login fix, trip copy fix

- Add Discord button to admin GitHub panel and user menu
- Sync all 13 translation files to 1434 keys with native translations
- Fix duplicate keys in Polish translation (pl.ts)
- Fix iOS login race condition: sameSite strict→lax, loadUser sequence counter
- Fix trip copy route: add missing db, Trip, TRIP_SELECT imports

client/src/store/authStore.ts

@@ -48,6 +48,9 @@ interface AuthState {
   demoLogin: () => Promise<AuthResponse>
 }
 
+// Sequence counter to prevent stale loadUser responses from overwriting fresh auth state
+let authSequence = 0
+
 export const useAuthStore = create<AuthState>((set, get) => ({
   user: null,
   isAuthenticated: false,
@@ -61,6 +64,7 @@ export const useAuthStore = create<AuthState>((set, get) => ({
   tripRemindersEnabled: false,
 
   login: async (email: string, password: string) => {
+    authSequence++
     set({ isLoading: true, error: null })
     try {
       const data = await authApi.login({ email, password }) as AuthResponse & { mfa_required?: boolean; mfa_token?: string }
@@ -84,6 +88,7 @@ export const useAuthStore = create<AuthState>((set, get) => ({
   },
 
   completeMfaLogin: async (mfaToken: string, code: string) => {
+    authSequence++
     set({ isLoading: true, error: null })
     try {
       const data = await authApi.verifyMfaLogin({ mfa_token: mfaToken, code: code.replace(/\s/g, '') })
@@ -103,6 +108,7 @@ export const useAuthStore = create<AuthState>((set, get) => ({
   },
 
   register: async (username: string, email: string, password: string, invite_token?: string) => {
+    authSequence++
     set({ isLoading: true, error: null })
     try {
       const data = await authApi.register({ username, email, password, invite_token })
@@ -138,10 +144,12 @@ export const useAuthStore = create<AuthState>((set, get) => ({
   },
 
   loadUser: async (opts?: { silent?: boolean }) => {
+    const seq = authSequence
     const silent = !!opts?.silent
     if (!silent) set({ isLoading: true })
     try {
       const data = await authApi.me()
+      if (seq !== authSequence) return // stale response — a login/register happened meanwhile
       set({
         user: data.user,
         isAuthenticated: true,
@@ -149,6 +157,7 @@ export const useAuthStore = create<AuthState>((set, get) => ({
       })
       connect()
     } catch (err: unknown) {
+      if (seq !== authSequence) return // stale response — ignore
       // Only clear auth state on 401 (invalid/expired token), not on network errors
       const isAuthError = err && typeof err === 'object' && 'response' in err &&
         (err as { response?: { status?: number } }).response?.status === 401
@@ -219,6 +228,7 @@ export const useAuthStore = create<AuthState>((set, get) => ({
   setTripRemindersEnabled: (val: boolean) => set({ tripRemindersEnabled: val }),
 
   demoLogin: async () => {
+    authSequence++
     set({ isLoading: true, error: null })
     try {
       const data = await authApi.demoLogin()