Implement Phase 2 features for Campaign Command Center

Adds 14 new features across the dashboard:
- Deal Risk Scoring (0-100) with risk factors on pipeline deals
- Account Health Score with multi-factor analysis on account cards
- Next Best Action Engine on Executive Overview
- Account Notes with pin/edit/delete in activity overlay and account detail
- Stakeholder Contact Map with role, sentiment, email, LinkedIn
- Competitive Intelligence Tracker with multi-select competitors and filtering
- CSV/Excel Export on accounts, activities, and pipeline pages
- Data Quality Dashboard in admin with completeness scoring
- Campaign Playbook Templates with 5 default plays and account progress tracking
- Goals & District Targets with quarterly tracking and progress bars
- Weekly Status Report (printable) and Executive Summary (printable)
- Activity Effectiveness Scoring showing pipeline conversion by activity type
- Mobile Activity FAB for quick activity logging on mobile
- Multi-User Auth (NextAuth + Google OAuth, @broadcom.com domain, role-based)

Also adds Phase 2 API route, scoring utilities, sidebar navigation updates,
and database schema extensions for notes, contacts, snapshots, playbooks,
and district targets.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/auth/error/page.tsx

@@ -0,0 +1,39 @@
+'use client';
+
+import Link from 'next/link';
+import { useSearchParams } from 'next/navigation';
+import { Suspense } from 'react';
+
+function ErrorContent() {
+  const params = useSearchParams();
+  const error = params.get('error');
+
+  const messages: Record<string, string> = {
+    AccessDenied: 'Only @broadcom.com accounts are allowed.',
+    Configuration: 'Auth is not configured yet. Set GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET in .env.local.',
+    Default: 'An authentication error occurred.',
+  };
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-[#F4F6F8]">
+      <div className="w-full max-w-sm bg-white rounded-2xl shadow-xl border border-gray-100 p-8 text-center">
+        <div className="w-14 h-14 mx-auto mb-4 rounded-full bg-red-50 flex items-center justify-center">
+          <svg className="w-7 h-7 text-red-500" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><circle cx="12" cy="12" r="10" /><line x1="15" y1="9" x2="9" y2="15" /><line x1="9" y1="9" x2="15" y2="15" /></svg>
+        </div>
+        <h1 className="text-lg font-bold text-[#1B1D36] mb-2">Access Denied</h1>
+        <p className="text-sm text-gray-500 mb-6">{messages[error || ''] || messages.Default}</p>
+        <Link href="/auth/signin" className="inline-block px-6 py-2.5 bg-[#0098C7] text-white text-sm font-semibold rounded-xl hover:bg-[#007ba3] transition">
+          Try Again
+        </Link>
+      </div>
+    </div>
+  );
+}
+
+export default function AuthErrorPage() {
+  return (
+    <Suspense fallback={<div className="min-h-screen flex items-center justify-center">Loading...</div>}>
+      <ErrorContent />
+    </Suspense>
+  );
+}