feat: improve user onboarding and setup UX (#1436)

* feat: add beginner onboarding and mode switching flow

* chore: ignore local gh auth config

* fix: restore kline fallback and align onboarding language

---------

Co-authored-by: zavier-bin <zhaobbbhhh@gmail.com>

web/src/lib/onboarding.ts

@@ -0,0 +1,28 @@
+export type UserMode = 'beginner' | 'advanced'
+
+const USER_MODE_KEY = 'nofx_user_mode'
+const BEGINNER_WALLET_ADDRESS_KEY = 'nofx_beginner_wallet_address'
+
+export function getUserMode(): UserMode | null {
+  const value = localStorage.getItem(USER_MODE_KEY)
+  if (value === 'beginner' || value === 'advanced') {
+    return value
+  }
+  return null
+}
+
+export function setUserMode(mode: UserMode) {
+  localStorage.setItem(USER_MODE_KEY, mode)
+}
+
+export function getPostAuthPath(mode: UserMode | null | undefined): string {
+  return mode === 'beginner' ? '/welcome' : '/traders'
+}
+
+export function setBeginnerWalletAddress(address: string) {
+  localStorage.setItem(BEGINNER_WALLET_ADDRESS_KEY, address)
+}
+
+export function getBeginnerWalletAddress(): string | null {
+  return localStorage.getItem(BEGINNER_WALLET_ADDRESS_KEY)
+}