Implement all core features: Knowledge pipeline, RAG chat, Todos, Habits, Study Cards, Tags, Dashboard

- Google OAuth authentication with callback flow
- Knowledge ingest pipeline (TEXT/WEB/YOUTUBE → chunking → categorization → embedding)
- OCI GenAI integration (chat, embeddings) with multi-model support
- Semantic search via Oracle VECTOR_DISTANCE
- RAG-based AI chat with source attribution
- Todos with subtasks, filters, and priority levels
- Habits with daily check-in, streak tracking, and color customization
- Study Cards with SM-2 spaced repetition and LLM auto-generation
- Tags system with knowledge item mapping
- Dashboard with live data from all modules

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sundol-frontend/src/app/login/page.tsx

@@ -1,25 +1,32 @@
 "use client";
 
-import { useState } from "react";
+import { useEffect } from "react";
 import { useRouter } from "next/navigation";
 import { useAuth } from "@/lib/auth-context";
 
+const GOOGLE_CLIENT_ID = process.env.NEXT_PUBLIC_GOOGLE_CLIENT_ID || "";
+const REDIRECT_URI = `${typeof window !== "undefined" ? window.location.origin : ""}/login/callback`;
+
 export default function LoginPage() {
   const router = useRouter();
-  const { login } = useAuth();
-  const [isLoading, setIsLoading] = useState(false);
+  const { isAuthenticated, isLoading } = useAuth();
 
-  const handleGoogleLogin = async () => {
-    setIsLoading(true);
-    try {
-      // TODO: Implement Google OAuth flow
-      // For now, placeholder
-      alert("Google OAuth not configured yet");
-    } catch (error) {
-      console.error("Login failed:", error);
-    } finally {
-      setIsLoading(false);
+  useEffect(() => {
+    if (!isLoading && isAuthenticated) {
+      router.replace("/dashboard");
     }
+  }, [isAuthenticated, isLoading, router]);
+
+  const handleGoogleLogin = () => {
+    const params = new URLSearchParams({
+      client_id: GOOGLE_CLIENT_ID,
+      redirect_uri: REDIRECT_URI,
+      response_type: "code",
+      scope: "openid email profile",
+      access_type: "offline",
+      prompt: "consent",
+    });
+    window.location.href = `https://accounts.google.com/o/oauth2/v2/auth?${params.toString()}`;
   };
 
   return (
@@ -33,8 +40,7 @@ export default function LoginPage() {
         </div>
         <button
           onClick={handleGoogleLogin}
-          disabled={isLoading}
-          className="w-full py-3 px-4 bg-white text-gray-800 rounded-lg font-medium hover:bg-gray-100 transition-colors disabled:opacity-50 flex items-center justify-center gap-3"
+          className="w-full py-3 px-4 bg-white text-gray-800 rounded-lg font-medium hover:bg-gray-100 transition-colors flex items-center justify-center gap-3"
         >
           <svg className="w-5 h-5" viewBox="0 0 24 24">
             <path fill="#4285F4" d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92a5.06 5.06 0 0 1-2.2 3.32v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.1z"/>
@@ -42,7 +48,7 @@ export default function LoginPage() {
             <path fill="#FBBC05" d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"/>
             <path fill="#EA4335" d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"/>
           </svg>
-          {isLoading ? "Signing in..." : "Sign in with Google"}
+          Sign in with Google
         </button>
       </div>
     </div>