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>

backend/server.js

@@ -18,7 +18,6 @@ const createUsersRouter = require('./routes/users');
 const createAuditLogRouter = require('./routes/auditLog');
 const logAudit = require('./helpers/auditLog');
 const createNvdLookupRouter = require('./routes/nvdLookup');
-const createWeeklyReportsRouter = require('./routes/weeklyReports');
 const createKnowledgeBaseRouter = require('./routes/knowledgeBase');
 const createArcherTicketsRouter = require('./routes/archerTickets');
 const createIvantiWorkflowsRouter = require('./routes/ivantiWorkflows');
@@ -175,9 +174,6 @@ const upload = multer({
     limits: { fileSize: 10 * 1024 * 1024 } // 10MB limit
 });
 
-// Weekly reports routes (editor/admin for upload, all authenticated for download)
-app.use('/api/weekly-reports', createWeeklyReportsRouter(db, upload));
-
 // Knowledge base routes (editor/admin for upload/delete, all authenticated for view)
 app.use('/api/knowledge-base', createKnowledgeBaseRouter(db, upload));