Sprint 6: Monthly actuals input, reconciliation, and file attachments

Add spreadsheet-style Monthly Actuals page for entering monthly actuals
against budget with auto-generated journal entries and reconciliation flag.
Add file attachment support (PDF, images, spreadsheets) on journal entries
for receipts and invoices. Enhance Budget vs Actual report with month
filter dropdown. Add reconciled badge to Transactions page. Replace bcrypt
with bcryptjs to fix Docker cross-platform native binding issues.

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

frontend/src/pages/reports/BudgetVsActualPage.tsx

@@ -27,8 +27,25 @@ interface BudgetVsActualData {
   total_expense_actual: number;
 }
 
+const monthFilterOptions = [
+  { value: '', label: 'Full Year' },
+  { value: '1', label: 'January' },
+  { value: '2', label: 'February' },
+  { value: '3', label: 'March' },
+  { value: '4', label: 'April' },
+  { value: '5', label: 'May' },
+  { value: '6', label: 'June' },
+  { value: '7', label: 'July' },
+  { value: '8', label: 'August' },
+  { value: '9', label: 'September' },
+  { value: '10', label: 'October' },
+  { value: '11', label: 'November' },
+  { value: '12', label: 'December' },
+];
+
 export function BudgetVsActualPage() {
   const [year, setYear] = useState(new Date().getFullYear().toString());
+  const [month, setMonth] = useState('');
 
   const yearOptions = Array.from({ length: 5 }, (_, i) => {
     const y = new Date().getFullYear() - 2 + i;
@@ -36,9 +53,10 @@ export function BudgetVsActualPage() {
   });
 
   const { data, isLoading } = useQuery<BudgetVsActualData>({
-    queryKey: ['budget-vs-actual', year],
+    queryKey: ['budget-vs-actual', year, month],
     queryFn: async () => {
-      const { data } = await api.get(`/budgets/${year}/vs-actual`);
+      const params = month ? `?month=${month}` : '';
+      const { data } = await api.get(`/budgets/${year}/vs-actual${params}`);
       return data;
     },
   });
@@ -127,7 +145,17 @@ export function BudgetVsActualPage() {
     <Stack>
       <Group justify="space-between">
         <Title order={2}>Budget vs. Actual</Title>
-        <Select data={yearOptions} value={year} onChange={(v) => v && setYear(v)} w={120} />
+        <Group>
+          <Select data={yearOptions} value={year} onChange={(v) => v && setYear(v)} w={100} />
+          <Select
+            data={monthFilterOptions}
+            value={month}
+            onChange={(v) => setMonth(v || '')}
+            w={150}
+            placeholder="Month"
+            clearable={false}
+          />
+        </Group>
       </Group>
 
       <SimpleGrid cols={{ base: 1, sm: 4 }}>