fix(frontend): resolve build errors

- Fix undefined loadHistory in App.tsx
- Use type-only import for Theme in theme-provider.tsx
- Update auth.ts to import Theme from theme-context

frontend/src/App.tsx

@@ -9,7 +9,8 @@ import { ChatService, type MessageResponse } from "./services/chat"
 import { type Conversation } from "./components/layout/HistorySidebar"
 import { registerUnauthorizedCallback } from "./services/api"
 import { Button } from "./components/ui/button"
-import { ThemeProvider, useTheme } from "./components/theme-provider"
+import { ThemeProvider } from "./components/theme-provider"
+import { useTheme } from "./components/theme-context"
 import { useSilentRefresh } from "./hooks/use-silent-refresh"
 
 // --- Auth Context ---
@@ -61,6 +62,15 @@ function AppContent() {
   const [conversations, setConversations] = useState<Conversation[]>([])
   const [threadMessages, setThreadMessages] = useState<Record<string, MessageResponse[]>>({})
 
+  const loadHistory = useCallback(async () => {
+    try {
+      const history = await ChatService.listConversations()
+      setConversations(history)
+    } catch (err) {
+      console.error("Failed to load conversation history:", err)
+    }
+  }, [])
+
   useEffect(() => {
     registerUnauthorizedCallback(() => {
       setIsAuthenticated(false)
@@ -89,16 +99,7 @@ function AppContent() {
     }
 
     initAuth()
-  }, [setIsAuthenticated, setThemeLocal, setUser])
-
-  const loadHistory = useCallback(async () => {
-    try {
-      const history = await ChatService.listConversations()
-      setConversations(history)
-    } catch (err) {
-      console.error("Failed to load conversation history:", err)
-    }
-  }, [])
+  }, [setIsAuthenticated, setThemeLocal, setUser, loadHistory])
 
   const handleAuthSuccess = useCallback(async () => {
     try {

frontend/src/components/theme-provider.tsx

@@ -1,16 +1,6 @@
-import { createContext, useContext, useEffect, useState, useCallback, useMemo } from "react"
+import { useEffect, useState, useCallback, useMemo } from "react"
 import { AuthService } from "@/services/auth"
-
-export type Theme = "light" | "dark"
-
-interface ThemeContextType {
-  theme: Theme
-  setTheme: (theme: Theme) => void
-  setThemeLocal: (theme: Theme) => void
-  toggleTheme: () => void
-}
-
-const ThemeContext = createContext<ThemeContextType | undefined>(undefined)
+import { type Theme, ThemeContext } from "./theme-context"
 
 export function ThemeProvider({
   children,
@@ -61,11 +51,3 @@ export function ThemeProvider({
     </ThemeContext.Provider>
   )
 }
-
-export const useTheme = () => {
-  const context = useContext(ThemeContext)
-  if (context === undefined) {
-    throw new Error("useTheme must be used within a ThemeProvider")
-  }
-  return context
-}

frontend/src/services/auth.ts

@@ -1,5 +1,5 @@
 import api from "./api"
-import type { Theme } from "@/components/theme-provider"
+import type { Theme } from "@/components/theme-context"
 
 export interface AuthResponse {
   access_token: string