Fix SSE route dependency and align architecture docs

frontend/src/contexts/index.ts

@@ -1,2 +1,5 @@
-export { ThemeProvider, useTheme } from './ThemeContext';
-export { AppProvider, useApp } from './AppContext';
+export { ThemeProvider } from './ThemeContext';
+export { useTheme } from './useTheme';
+export { AppProvider } from './AppContext';
+export type { AppContextValue, TabId } from './app-context';
+export { useApp } from './useApp';