add api client and auth store

apiFetch wrapper sends JSON with credentials, parses error
shapes off the backend's {error: '...'} responses, and exposes
typed helpers (apiGet, apiPost, apiDelete). Auth store now
drives the real /signup -> /confirm-email -> /login -> /me ->
/logout flow. Vite dev proxy points /api at the backend on
:8000.

frontend/blog_portal/src/api/client.ts

@@ -0,0 +1,68 @@
+const API_BASE = (import.meta.env.VITE_API_BASE as string | undefined) ?? "/api";
+
+export interface ApiResult<T> {
+  ok: boolean;
+  status: number;
+  data: T | null;
+  error: string | null;
+}
+
+export async function apiFetch<T>(path: string, init?: RequestInit): Promise<ApiResult<T>> {
+  const response = await fetch(`${API_BASE}${path}`, {
+    credentials: "include",
+    headers: {
+      Accept: "application/json",
+      ...(init?.body ? { "Content-Type": "application/json" } : {}),
+      ...init?.headers,
+    },
+    ...init,
+  });
+
+  let payload: unknown = null;
+  const text = await response.text();
+  if (text.length > 0) {
+    try {
+      payload = JSON.parse(text) as unknown;
+    } catch {
+      payload = null;
+    }
+  }
+
+  if (!response.ok) {
+    const errorMessage =
+      payload &&
+      typeof payload === "object" &&
+      "error" in payload &&
+      typeof (payload as { error: unknown }).error === "string"
+        ? (payload as { error: string }).error
+        : `request failed: ${response.status}`;
+    return {
+      ok: false,
+      status: response.status,
+      data: null,
+      error: errorMessage,
+    };
+  }
+
+  return {
+    ok: true,
+    status: response.status,
+    data: payload as T,
+    error: null,
+  };
+}
+
+export function apiGet<T>(path: string): Promise<ApiResult<T>> {
+  return apiFetch<T>(path, { method: "GET" });
+}
+
+export function apiPost<T>(path: string, body: unknown): Promise<ApiResult<T>> {
+  return apiFetch<T>(path, {
+    method: "POST",
+    body: JSON.stringify(body ?? {}),
+  });
+}
+
+export function apiDelete<T>(path: string): Promise<ApiResult<T>> {
+  return apiFetch<T>(path, { method: "DELETE" });
+}

frontend/blog_portal/src/stores/auth.ts

@@ -1,5 +1,6 @@
 import { defineStore } from "pinia";
-import { ref } from "vue";
+import { computed, ref } from "vue";
+import { apiGet, apiPost } from "@/api/client";
 
 export interface AuthUser {
   id: number;
@@ -8,18 +9,78 @@ export interface AuthUser {
   isAdmin: boolean;
 }
 
+interface MePayload {
+  user: AuthUser;
+}
+
 export const useAuthStore = defineStore("auth", () => {
   const user = ref<AuthUser | null>(null);
   const checked = ref(false);
   const error = ref<string | null>(null);
+  const signupCompleted = ref(false);
+
+  const isAuthenticated = computed(() => user.value !== null);
+  const isAdmin = computed(() => user.value?.isAdmin === true);
 
   async function fetchMe(): Promise<boolean> {
+    const result = await apiGet<MePayload>("/me");
     checked.value = true;
+    if (result.ok && result.data) {
+      user.value = result.data.user;
+      return true;
+    }
+    user.value = null;
     return false;
   }
 
+  async function signup(email: string, displayName: string): Promise<boolean> {
+    error.value = null;
+    const result = await apiPost<null>("/signup", {
+      email,
+      displayName,
+    });
+    if (!result.ok) {
+      error.value = result.error;
+      return false;
+    }
+    signupCompleted.value = true;
+    return true;
+  }
+
+  async function confirmEmail(token: string, password: string): Promise<boolean> {
+    error.value = null;
+    const result = await apiPost<null>("/confirm-email", {
+      token,
+      password,
+    });
+    if (!result.ok) {
+      error.value = result.error;
+      return false;
+    }
+    return true;
+  }
+
+  async function login(email: string, password: string): Promise<boolean> {
+    error.value = null;
+    const result = await apiPost<MePayload>("/login", {
+      email,
+      password,
+    });
+    if (!result.ok) {
+      error.value = result.error;
+      return false;
+    }
+    if (result.data) {
+      user.value = result.data.user;
+      checked.value = true;
+    }
+    return true;
+  }
+
   async function logout(): Promise<void> {
+    await apiPost<null>("/logout", {});
     user.value = null;
+    signupCompleted.value = false;
   }
 
   function clearError(): void {
@@ -30,7 +91,13 @@ export const useAuthStore = defineStore("auth", () => {
     user,
     checked,
     error,
+    signupCompleted,
+    isAuthenticated,
+    isAdmin,
     fetchMe,
+    signup,
+    confirmEmail,
+    login,
     logout,
     clearError,
   };

frontend/blog_portal/vite.config.ts

@@ -7,14 +7,18 @@ import vueDevTools from 'vite-plugin-vue-devtools'
 
 // https://vite.dev/config/
 export default defineConfig({
-  plugins: [
-    vue(),
-    vueJsx(),
-    vueDevTools(),
-  ],
+  plugins: [vue(), vueJsx(), vueDevTools()],
   resolve: {
     alias: {
-      '@': fileURLToPath(new URL('./src', import.meta.url))
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+    },
+  },
+  server: {
+    proxy: {
+      '/api': {
+        target: 'http://localhost:8000',
+        changeOrigin: true,
+      },
     },
   },
 })