Add multiple entries per day, user management, reminders, and AI reflections

- Multiple entries per day: Home page now starts fresh, Save & New button
- Admin user management: Add/delete users, reset passwords, toggle admin
- Daily reminders: Browser notifications at configurable time
- AI reflections: Generate insights from entries using Claude API
- Remove cloud sync placeholder (already have user accounts)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/api/entries/route.ts

@@ -66,7 +66,7 @@ export async function GET(request: NextRequest) {
   }
 }
 
-// POST /api/entries - Create or update today's entry
+// POST /api/entries - Create a new entry or update existing by id
 export async function POST(request: NextRequest) {
   const user = await getSession();
   if (!user) {
@@ -75,31 +75,33 @@ export async function POST(request: NextRequest) {
 
   try {
     const body: CreateEntryRequest = await request.json();
-    const { date, text, mood, roughDay, tagNames } = body;
+    const { id: existingId, date, text, mood, roughDay, tagNames } = body;
 
     if (!date || !text) {
       return NextResponse.json({ error: "Date and text are required" }, { status: 400 });
     }
 
     const now = Date.now();
-
-    // Check if entry exists for this date for this user
-    const existing = await db
-      .select()
-      .from(schema.entries)
-      .where(
-        and(
-          eq(schema.entries.userId, user.id),
-          eq(schema.entries.date, date)
-        )
-      )
-      .limit(1);
-
     let entryId: string;
 
-    if (existing.length > 0) {
-      // Update existing entry
-      entryId = existing[0].id;
+    if (existingId) {
+      // Update existing entry - verify ownership
+      const existing = await db
+        .select()
+        .from(schema.entries)
+        .where(
+          and(
+            eq(schema.entries.id, existingId),
+            eq(schema.entries.userId, user.id)
+          )
+        )
+        .limit(1);
+
+      if (existing.length === 0) {
+        return NextResponse.json({ error: "Entry not found" }, { status: 404 });
+      }
+
+      entryId = existingId;
       await db
         .update(schema.entries)
         .set({