refactor: remove login/auth for public dashboard

- Remove login page, redirect / to /dashboard directly
- Remove AuthProvider, DashboardGuard from dashboard layout
- Remove use-auth hook and auth API module
- Remove X-Admin-Password header from API client
- Remove logout button from sidebar

services/frontend/src/lib/api/auth.ts

@@ -1,13 +0,0 @@
-import { ApiError, api } from "./client";
-
-export async function login(password: string): Promise<boolean> {
-  try {
-    const resp = await api.post<{ ok: boolean }>("/api/auth/login", {
-      password,
-    });
-    return resp.ok;
-  } catch (err) {
-    if (err instanceof ApiError) return false;
-    throw err;
-  }
-}

services/frontend/src/lib/api/client.ts

@@ -12,27 +12,17 @@ function getBaseUrl(): string {
   if (typeof window === "undefined") return "";
   const protocol = window.location.protocol.replace(":", "");
   const host = window.location.host;
-  // In dev, Next.js proxy can be configured, but default to same-host assumption
   return `${protocol}://${host}`;
 }
 
-function getAuthHeader(): string | null {
-  if (typeof window === "undefined") return null;
-  return localStorage.getItem("admin-password");
-}
-
 export async function apiRequest<T>(
   method: string,
   path: string,
   body?: unknown,
 ): Promise<T> {
   const url = `${getBaseUrl()}${path}`;
-  const password = getAuthHeader();
 
   const headers: Record<string, string> = {};
-  if (password) {
-    headers["X-Admin-Password"] = password;
-  }
   if (body !== undefined) {
     headers["Content-Type"] = "application/json";
   }

services/frontend/src/lib/api/index.ts

@@ -1,4 +1,3 @@
-export { login } from "./auth";
 export { ApiError, api, apiRequest } from "./client";
 export { configApi } from "./config";
 export { dashboardApi } from "./dashboard";