fix: budget save error and add read-only view mode (v2026.03.10)

Fix budget save 500 error caused by three data mismatches between
frontend and backend: wrapped payload ({lines:[...]}) vs expected
raw array, snake_case vs camelCase field names (account_id vs
accountId), and dec_amt vs dec for December values.

Add read-only budget view as default for existing budgets with an
"Edit Budget" button to enter edit mode, and Cancel to discard
changes - reducing accidental edits.

Bump version to 2026.03.10 across all packages and settings.

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

frontend/src/pages/budgets/BudgetsPage.tsx

@@ -4,7 +4,7 @@ import {
   Select, Loader, Center, Badge, Card, Alert,
 } from '@mantine/core';
 import { notifications } from '@mantine/notifications';
-import { IconDeviceFloppy, IconUpload, IconDownload, IconInfoCircle } from '@tabler/icons-react';
+import { IconDeviceFloppy, IconUpload, IconDownload, IconInfoCircle, IconPencil, IconX } from '@tabler/icons-react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import api from '../../services/api';
 import { useIsReadOnly } from '../../stores/authStore';
@@ -96,6 +96,7 @@ function parseCSV(text: string): Record<string, string>[] {
 export function BudgetsPage() {
   const [year, setYear] = useState(new Date().getFullYear().toString());
   const [budgetData, setBudgetData] = useState<BudgetLine[]>([]);
+  const [isEditing, setIsEditing] = useState(false);
   const queryClient = useQueryClient();
   const fileInputRef = useRef<HTMLInputElement>(null);
   const isReadOnly = useIsReadOnly();
@@ -105,6 +106,11 @@ export function BudgetsPage() {
   const incomeSectionBg = isDark ? 'var(--mantine-color-green-9)' : '#e6f9e6';
   const expenseSectionBg = isDark ? 'var(--mantine-color-red-9)' : '#fde8e8';
 
+  // Budget exists when there is data loaded for the selected year
+  const hasBudget = budgetData.length > 0;
+  // Cells are editable only when editing an existing budget or creating a new one (no data yet)
+  const cellsEditable = !isReadOnly && (isEditing || !hasBudget);
+
   const { isLoading } = useQuery<BudgetLine[]>({
     queryKey: ['budgets', year],
     queryFn: async () => {
@@ -112,25 +118,27 @@ export function BudgetsPage() {
       // Hydrate each line: ensure numbers and compute annual_total
       const hydrated = (data as any[]).map(hydrateBudgetLine);
       setBudgetData(hydrated);
+      setIsEditing(false); // Reset to view mode when year changes or data reloads
       return hydrated;
     },
   });
 
   const saveMutation = useMutation({
     mutationFn: async () => {
-      const lines = budgetData
+      const payload = budgetData
         .filter((b) => months.some((m) => (b as any)[m] > 0))
         .map((b) => ({
-          account_id: b.account_id,
-          fund_type: b.fund_type,
+          accountId: b.account_id,
+          fundType: b.fund_type,
           jan: b.jan, feb: b.feb, mar: b.mar, apr: b.apr,
           may: b.may, jun: b.jun, jul: b.jul, aug: b.aug,
-          sep: b.sep, oct: b.oct, nov: b.nov, dec_amt: b.dec_amt,
+          sep: b.sep, oct: b.oct, nov: b.nov, dec: b.dec_amt,
         }));
-      return api.put(`/budgets/${year}`, { lines });
+      return api.put(`/budgets/${year}`, payload);
     },
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['budgets', year] });
+      setIsEditing(false);
       notifications.show({ message: 'Budget saved', color: 'green' });
     },
     onError: (err: any) => {
@@ -227,6 +235,12 @@ export function BudgetsPage() {
     event.target.value = '';
   };
 
+  const handleCancelEdit = () => {
+    setIsEditing(false);
+    // Re-fetch to discard unsaved changes
+    queryClient.invalidateQueries({ queryKey: ['budgets', year] });
+  };
+
   const updateCell = (idx: number, month: string, value: number) => {
     const updated = [...budgetData];
     (updated[idx] as any)[month] = value || 0;
@@ -281,9 +295,35 @@ export function BudgetsPage() {
               accept=".csv,.txt"
               onChange={handleFileChange}
             />
-            <Button leftSection={<IconDeviceFloppy size={16} />} onClick={() => saveMutation.mutate()} loading={saveMutation.isPending}>
-              Save Budget
-            </Button>
+            {hasBudget && !isEditing ? (
+              <Button
+                variant="outline"
+                leftSection={<IconPencil size={16} />}
+                onClick={() => setIsEditing(true)}
+              >
+                Edit Budget
+              </Button>
+            ) : (
+              <>
+                {isEditing && (
+                  <Button
+                    variant="outline"
+                    color="gray"
+                    leftSection={<IconX size={16} />}
+                    onClick={handleCancelEdit}
+                  >
+                    Cancel
+                  </Button>
+                )}
+                <Button
+                  leftSection={<IconDeviceFloppy size={16} />}
+                  onClick={() => saveMutation.mutate()}
+                  loading={saveMutation.isPending}
+                >
+                  Save Budget
+                </Button>
+              </>
+            )}
           </>)}
         </Group>
       </Group>
@@ -397,16 +437,21 @@ export function BudgetsPage() {
                       </Table.Td>
                       {months.map((m) => (
                         <Table.Td key={m} p={2}>
-                          <NumberInput
-                            value={(line as any)[m] || 0}
-                            onChange={(v) => updateCell(idx, m, Number(v) || 0)}
-                            size="xs"
-                            hideControls
-                            decimalScale={2}
-                            min={0}
-                            disabled={isReadOnly}
-                            styles={{ input: { textAlign: 'right', fontFamily: 'monospace' } }}
-                          />
+                          {cellsEditable ? (
+                            <NumberInput
+                              value={(line as any)[m] || 0}
+                              onChange={(v) => updateCell(idx, m, Number(v) || 0)}
+                              size="xs"
+                              hideControls
+                              decimalScale={2}
+                              min={0}
+                              styles={{ input: { textAlign: 'right', fontFamily: 'monospace' } }}
+                            />
+                          ) : (
+                            <Text size="sm" ta="right" ff="monospace">
+                              {fmt((line as any)[m] || 0)}
+                            </Text>
+                          )}
                         </Table.Td>
                       ))}
                       <Table.Td ta="right" fw={500} ff="monospace">

frontend/src/pages/settings/SettingsPage.tsx

@@ -117,7 +117,7 @@ export function SettingsPage() {
             </Group>
             <Group justify="space-between">
               <Text size="sm" c="dimmed">Version</Text>
-              <Badge variant="light">2026.3.7 (Beta)</Badge>
+              <Badge variant="light">2026.03.10</Badge>
             </Group>
             <Group justify="space-between">
               <Text size="sm" c="dimmed">API</Text>