Cashup: add 'Load last count' receipts button on petty cash form

Fetches receipts from the most recent petty cash count and populates the
current form — for when the tin hasn't been replenished and slips carry over.

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

frontend/src/pages/FloatManagement.tsx

@@ -220,6 +220,7 @@ export function FloatCountForm({ type }: { type: CountType }) {
   const [receipts, setReceipts] = useState<Array<{ amount: string; description: string }>>([])
   const [notes, setNotes] = useState('')
   const [saving, setSaving] = useState(false)
+  const [loadingLast, setLoadingLast] = useState(false)
   const [error, setError] = useState<string | null>(null)
   const [savedRecord, setSavedRecord] = useState<DetailRecord | null>(null)
   const [changeTinTargets, setChangeTinTargets] = useState<Record<string, number>>({})
@@ -278,6 +279,21 @@ export function FloatCountForm({ type }: { type: CountType }) {
     }
   }
 
+  async function loadLastReceipts() {
+    setLoadingLast(true)
+    try {
+      const list = await api.get<{ rows: FloatCount[] }>('/floats?type=petty_cash&offset=0&limit=1')
+      if (!list.rows.length) { setError('No previous petty cash count found.'); return }
+      const detail = await api.get<DetailRecord>(`/floats/${list.rows[0].id}`)
+      if (!detail.receipts.length) { setError('Last count had no receipts.'); return }
+      setReceipts(detail.receipts.map(r => ({ amount: String(r.receipt_value), description: r.receipt_description || '' })))
+    } catch {
+      setError('Could not load last count.')
+    } finally {
+      setLoadingLast(false)
+    }
+  }
+
   function reset() {
     setSavedRecord(null)
     setDenomQtys({})
@@ -338,8 +354,13 @@ export function FloatCountForm({ type }: { type: CountType }) {
         <Card style={{ marginBottom: '1rem' }}>
           <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '0.75rem' }}>
             <h2 style={{ fontSize: '0.875rem', fontWeight: 700, color: 'var(--text-mid)' }}>RECEIPTS</h2>
+            <div style={{ display: 'flex', gap: '0.5rem' }}>
+              <Btn small variant="ghost" disabled={loadingLast} onClick={loadLastReceipts}>
+                {loadingLast ? 'Loading…' : 'Load last count'}
+              </Btn>
               <Btn small variant="ghost" onClick={() => setReceipts(r => [...r, { amount: '', description: '' }])}>+ Add</Btn>
             </div>
+          </div>
           {receipts.map((r, i) => (
             <div key={i} style={{ display: 'grid', gridTemplateColumns: '100px 1fr 32px', gap: '0.4rem', marginBottom: '0.35rem', alignItems: 'center' }}>
               <input type="number" min="0" step="0.01" value={r.amount} placeholder="0.00"