feat: implement platform management system with authentication and dashboard

- Add PlatformUser model with roles (SUPER_ADMIN, ADMIN, SUPPORT)
- Implement platform authentication with NextAuth
- Create platform dashboard showing companies, users, and sessions
- Add platform API endpoints for company management
- Update landing page with SaaS design
- Include test improvements and accessibility updates

app/api/platform/companies/[id]/route.ts

@@ -0,0 +1,125 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getServerSession } from "next-auth";
+import { platformAuthOptions } from "../../auth/[...nextauth]/route";
+import { prisma } from "../../../../../lib/prisma";
+import { CompanyStatus } from "@prisma/client";
+
+// GET /api/platform/companies/[id] - Get company details
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const session = await getServerSession(platformAuthOptions);
+
+    if (!session?.user?.isPlatformUser) {
+      return NextResponse.json({ error: "Platform access required" }, { status: 401 });
+    }
+
+    const { id } = await params;
+
+    const company = await prisma.company.findUnique({
+      where: { id },
+      include: {
+        users: {
+          select: {
+            id: true,
+            email: true,
+            role: true,
+            createdAt: true,
+            updatedAt: true,
+          },
+        },
+        sessions: {
+          select: {
+            id: true,
+            startTime: true,
+            endTime: true,
+            sentiment: true,
+            category: true,
+          },
+          take: 10,
+          orderBy: { createdAt: "desc" },
+        },
+        _count: {
+          select: {
+            sessions: true,
+            imports: true,
+            users: true,
+          },
+        },
+      },
+    });
+
+    if (!company) {
+      return NextResponse.json({ error: "Company not found" }, { status: 404 });
+    }
+
+    return NextResponse.json({ company });
+  } catch (error) {
+    console.error("Platform company details error:", error);
+    return NextResponse.json({ error: "Internal server error" }, { status: 500 });
+  }
+}
+
+// PATCH /api/platform/companies/[id] - Update company
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const session = await getServerSession(platformAuthOptions);
+
+    if (!session?.user?.isPlatformUser || session.user.platformRole === "SUPPORT") {
+      return NextResponse.json({ error: "Admin access required" }, { status: 403 });
+    }
+
+    const { id } = await params;
+    const body = await request.json();
+    const { name, csvUrl, csvUsername, csvPassword, status } = body;
+
+    const updateData: any = {};
+    if (name !== undefined) updateData.name = name;
+    if (csvUrl !== undefined) updateData.csvUrl = csvUrl;
+    if (csvUsername !== undefined) updateData.csvUsername = csvUsername;
+    if (csvPassword !== undefined) updateData.csvPassword = csvPassword;
+    if (status !== undefined) updateData.status = status;
+
+    const company = await prisma.company.update({
+      where: { id },
+      data: updateData,
+    });
+
+    return NextResponse.json({ company });
+  } catch (error) {
+    console.error("Platform company update error:", error);
+    return NextResponse.json({ error: "Internal server error" }, { status: 500 });
+  }
+}
+
+// DELETE /api/platform/companies/[id] - Delete company (archives instead)
+export async function DELETE(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const session = await getServerSession(platformAuthOptions);
+
+    if (!session?.user?.isPlatformUser || session.user.platformRole !== "SUPER_ADMIN") {
+      return NextResponse.json({ error: "Super admin access required" }, { status: 403 });
+    }
+
+    const { id } = await params;
+
+    // Archive instead of delete to preserve data integrity
+    const company = await prisma.company.update({
+      where: { id },
+      data: { status: CompanyStatus.ARCHIVED },
+    });
+
+    return NextResponse.json({ company });
+  } catch (error) {
+    console.error("Platform company archive error:", error);
+    return NextResponse.json({ error: "Internal server error" }, { status: 500 });
+  }
+}