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/migrations/add_weekly_reports_table.js

@@ -1,59 +0,0 @@
-// Migration: Add weekly_reports table for vulnerability report uploads
-
-const sqlite3 = require('sqlite3').verbose();
-const path = require('path');
-
-const dbPath = path.join(__dirname, '..', 'cve_database.db');
-const db = new sqlite3.Database(dbPath);
-
-console.log('Running migration: add_weekly_reports_table');
-
-db.serialize(() => {
-  db.run(`
-    CREATE TABLE IF NOT EXISTS weekly_reports (
-      id INTEGER PRIMARY KEY AUTOINCREMENT,
-      upload_date DATE NOT NULL,
-      week_label VARCHAR(50),
-      original_filename VARCHAR(255),
-      processed_filename VARCHAR(255),
-      original_file_path VARCHAR(500),
-      processed_file_path VARCHAR(500),
-      row_count_original INTEGER,
-      row_count_processed INTEGER,
-      uploaded_by INTEGER,
-      uploaded_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-      is_current BOOLEAN DEFAULT 0,
-      FOREIGN KEY (uploaded_by) REFERENCES users(id)
-    )
-  `, (err) => {
-    if (err) {
-      console.error('Error creating weekly_reports table:', err);
-      process.exit(1);
-    }
-    console.log('✓ Created weekly_reports table');
-  });
-
-  db.run(`
-    CREATE INDEX IF NOT EXISTS idx_weekly_reports_date
-    ON weekly_reports(upload_date DESC)
-  `, (err) => {
-    if (err) {
-      console.error('Error creating date index:', err);
-      process.exit(1);
-    }
-    console.log('✓ Created index on upload_date');
-  });
-
-  db.run(`
-    CREATE INDEX IF NOT EXISTS idx_weekly_reports_current
-    ON weekly_reports(is_current)
-  `, (err) => {
-    if (err) {
-      console.error('Error creating current index:', err);
-      process.exit(1);
-    }
-    console.log('✓ Created index on is_current');
-    console.log('\nMigration completed successfully!');
-    db.close();
-  });
-});