Remove weekly report functionality

- Delete backend/routes/weeklyReports.js
- Delete backend/migrations/add_weekly_reports_table.js
- Delete backend/scripts/split_cve_report.py
- Delete backend/helpers/excelProcessor.js
- Delete frontend/src/components/WeeklyReportModal.js
- Remove import, state, button, and modal from App.js
- Remove route registration and require from server.js
- Drop weekly_reports table from SQLite database

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

frontend/src/App.js

@@ -6,7 +6,6 @@ import UserMenu from './components/UserMenu';
 import UserManagement from './components/UserManagement';
 import AuditLog from './components/AuditLog';
 import NvdSyncModal from './components/NvdSyncModal';
-import WeeklyReportModal from './components/WeeklyReportModal';
 import KnowledgeBaseModal from './components/KnowledgeBaseModal';
 import KnowledgeBaseViewer from './components/KnowledgeBaseViewer';
 import './App.css';
@@ -176,7 +175,6 @@ export default function App() {
   const [showUserManagement, setShowUserManagement] = useState(false);
   const [showAuditLog, setShowAuditLog] = useState(false);
   const [showNvdSync, setShowNvdSync] = useState(false);
-  const [showWeeklyReport, setShowWeeklyReport] = useState(false);
   const [showKnowledgeBase, setShowKnowledgeBase] = useState(false);
   const [knowledgeBaseArticles, setKnowledgeBaseArticles] = useState([]);
   const [selectedKBArticle, setSelectedKBArticle] = useState(null);
@@ -975,15 +973,6 @@ export default function App() {
                   NVD Sync
                 </button>
               )}
-              {canWrite() && (
-                <button
-                  onClick={() => setShowWeeklyReport(true)}
-                  className="intel-button intel-button-success relative z-10 flex items-center gap-2"
-                >
-                  <Upload className="w-4 h-4" />
-                  Weekly Report
-                </button>
-              )}
               {canWrite() && (
                 <button
                   onClick={() => setShowAddCVE(true)}
@@ -1037,11 +1026,6 @@ export default function App() {
           <NvdSyncModal onClose={() => setShowNvdSync(false)} onSyncComplete={() => fetchCVEs()} />
         )}
 
-        {/* Weekly Report Modal */}
-        {showWeeklyReport && (
-          <WeeklyReportModal onClose={() => setShowWeeklyReport(false)} />
-        )}
-
         {/* Knowledge Base Modal */}
         {showKnowledgeBase && (
           <KnowledgeBaseModal