feat: Google OAuth ile giris

- User modeline googleId (unique) eklendi
- google start/callback API route'lari (state korumali, find-or-create)
- Login/register sayfalarina Google butonu
- docker-compose'a GOOGLE_CLIENT_ID/SECRET env gecisi
- tsconfig.tsbuildinfo gitignore'a eklendi

src/app/api/auth/google/callback/route.ts

@@ -0,0 +1,89 @@
+import { NextResponse } from "next/server";
+import { cookies } from "next/headers";
+import { UserRole } from "@prisma/client";
+import { prisma } from "@/lib/db";
+import { createSession } from "@/lib/auth/session";
+import { isConfiguredAdminEmail } from "@/lib/admin-emails";
+import { exchangeGoogleCode, fetchGoogleProfile, GOOGLE_STATE_COOKIE } from "@/lib/auth/google";
+
+function redirectToLogin(error: string) {
+  return NextResponse.redirect(
+    new URL(`/login?error=${encodeURIComponent(error)}`, process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000")
+  );
+}
+
+export async function GET(req: Request) {
+  const url = new URL(req.url);
+  const code = url.searchParams.get("code");
+  const state = url.searchParams.get("state");
+  const oauthError = url.searchParams.get("error");
+
+  if (oauthError) return redirectToLogin(oauthError);
+
+  const cookieStore = await cookies();
+  const expectedState = cookieStore.get(GOOGLE_STATE_COOKIE)?.value;
+  cookieStore.delete(GOOGLE_STATE_COOKIE);
+
+  if (!code || !state || !expectedState || state !== expectedState) {
+    return redirectToLogin("GOOGLE_STATE_MISMATCH");
+  }
+
+  let tokens;
+  try {
+    tokens = await exchangeGoogleCode(code);
+  } catch (err) {
+    console.error("[google/callback] token exchange failed:", err);
+    return redirectToLogin("GOOGLE_AUTH_FAILED");
+  }
+
+  let profile;
+  try {
+    profile = await fetchGoogleProfile(tokens.access_token);
+  } catch (err) {
+    console.error("[google/callback] profile fetch failed:", err);
+    return redirectToLogin("GOOGLE_AUTH_FAILED");
+  }
+
+  if (!profile.sub) return redirectToLogin("GOOGLE_AUTH_FAILED");
+
+  const email = (profile.email || "").trim().toLowerCase();
+  if (!email) return redirectToLogin("GOOGLE_EMAIL_REQUIRED");
+
+  const isAdmin = isConfiguredAdminEmail(email);
+  const plan = await prisma.plan.findUnique({ where: { code: isAdmin ? "PREMIUM" : "FREE" } });
+
+  let user = await prisma.user.findUnique({ where: { googleId: profile.sub } });
+  if (!user) {
+    user = await prisma.user.findUnique({ where: { email } });
+  }
+
+  if (!user) {
+    if (!plan) return redirectToLogin("PLAN_NOT_SEEDED");
+    user = await prisma.user.create({
+      data: {
+        email,
+        googleId: profile.sub,
+        name: profile.name || email.split("@")[0],
+        avatarUrl: profile.picture || null,
+        locale: profile.locale || "tr",
+        role: isAdmin ? UserRole.ADMIN : UserRole.USER,
+        subscription: { create: { planId: plan.id, status: "ACTIVE" } }
+      }
+    });
+  } else {
+    user = await prisma.user.update({
+      where: { id: user.id },
+      data: {
+        googleId: user.googleId || profile.sub,
+        name: user.name || profile.name || null,
+        avatarUrl: user.avatarUrl || profile.picture || null,
+        lastLoginAt: new Date()
+      }
+    });
+  }
+
+  await createSession(user.id);
+  return NextResponse.redirect(
+    new URL("/dashboard/ads", process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000")
+  );
+}

src/app/api/auth/google/start/route.ts

@@ -0,0 +1,32 @@
+import { NextResponse } from "next/server";
+import { cookies } from "next/headers";
+import { randomToken } from "@/lib/auth/crypto";
+import { googleAuthUrl, googleConfig, GOOGLE_STATE_COOKIE } from "@/lib/auth/google";
+
+export async function GET() {
+  const config = googleConfig();
+  if (!config) {
+    return NextResponse.redirect(
+      new URL("/login?error=GOOGLE_NOT_CONFIGURED", process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000")
+    );
+  }
+
+  const state = randomToken(16);
+  const cookieStore = await cookies();
+  cookieStore.set(GOOGLE_STATE_COOKIE, state, {
+    httpOnly: true,
+    sameSite: "lax",
+    secure: process.env.NODE_ENV === "production",
+    path: "/",
+    maxAge: 600
+  });
+
+  const authUrl = googleAuthUrl(state);
+  if (!authUrl) {
+    return NextResponse.redirect(
+      new URL("/login?error=GOOGLE_NOT_CONFIGURED", process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000")
+    );
+  }
+
+  return NextResponse.redirect(authUrl);
+}