feat(calendar): click due-date day to navigate to filtered Reporting view

- CalendarWidget accepts onDateClick prop; due-date cells are clickable
  with pointer cursor, red hover highlight, and updated tooltip
- App.js wires onDateClick: sets calendarFilter state and navigates to
  the Reporting page
- NavDrawer navigation to Reporting clears calendarFilter so it only
  applies on calendar-initiated navigation
- ReportingPage accepts filterDate prop; initializes columnFilters with
  { dueDate: Set([filterDate]) } so the view lands pre-filtered
- Existing Clear Filters button lets the user dismiss the filter normally

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

frontend/src/App.js

@@ -178,6 +178,7 @@ export default function App() {
   const [quickCheckResult, setQuickCheckResult] = useState(null);
   const [currentPage, setCurrentPage] = useState('home');
   const [navOpen, setNavOpen] = useState(false);
+  const [calendarFilter, setCalendarFilter] = useState(null);
   const [showAddCVE, setShowAddCVE] = useState(false);
   const [showUserManagement, setShowUserManagement] = useState(false);
   const [showAuditLog, setShowAuditLog] = useState(false);
@@ -961,7 +962,11 @@ export default function App() {
         isOpen={navOpen}
         onClose={() => setNavOpen(false)}
         currentPage={currentPage}
-        onNavigate={setCurrentPage}
+        onNavigate={(page) => {
+          // Clear calendar filter when navigating directly via the nav drawer
+          if (page === 'reporting') setCalendarFilter(null);
+          setCurrentPage(page);
+        }}
       />
       {/* Scanning line effect */}
       <div className="scan-line"></div>
@@ -1036,7 +1041,7 @@ export default function App() {
         </div>
 
         {/* Page content */}
-        {currentPage === 'reporting'      && <ReportingPage />}
+        {currentPage === 'reporting'      && <ReportingPage filterDate={calendarFilter} />}
         {currentPage === 'knowledge-base' && <KnowledgeBasePage />}
         {currentPage === 'exports'        && <ExportsPage />}
 
@@ -2220,7 +2225,12 @@ export default function App() {
                 Calendar
               </h2>
 
-              <CalendarWidget />
+              <CalendarWidget
+                onDateClick={(dateStr) => {
+                  setCalendarFilter(dateStr);
+                  setCurrentPage('reporting');
+                }}
+              />
             </div>
 
             {/* Open Vendor Tickets */}