Add HeXi bot codebase: custom plugins, web frontends, tests

- hexi core: message handling, rate limiting, cooldown, plugin manager
- Custom plugins: BF stats, daily check-in, quotes, persona cards, etc.
- Community plugins vendored under hexi/plugins with local fixes
- Web admin frontends (learning-chat, persona-admin), unified hexi/web
- Tests for rate_limit/cooldown/memes/persona; poetry.lock

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

hexi/web/src/auth/auth.tsx

@@ -0,0 +1,30 @@
+import { createContext, useContext, useState, type ReactNode } from 'react'
+import { authLogin, clearSession, getUserName, setSession } from '../api/client'
+
+interface AuthState {
+  token: string
+  username: string
+  login: (u: string, p: string) => Promise<void>
+  logout: () => void
+}
+
+const Ctx = createContext<AuthState>({ token: '', username: '', login: async () => {}, logout: () => {} })
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [token, setToken] = useState(() => localStorage.getItem('hexi_web_token') || '')
+  const [username, setUsername] = useState(() => localStorage.getItem('hexi_web_username') || '')
+  const login = async (u: string, p: string) => {
+    const data = await authLogin(u, p)
+    setSession(data.token, data.username)
+    setToken(data.token)
+    setUsername(data.username)
+  }
+  const logout = () => {
+    clearSession()
+    setToken('')
+    setUsername('')
+  }
+  return <Ctx.Provider value={{ token, username, login, logout }}>{children}</Ctx.Provider>
+}
+
+export const useAuth = () => useContext(Ctx)