fix(wallet): blank send/receive on every open; sweep shows amount; camera option stays visible

Operator-reported (2026-08-05):

- Send/Receive modals reset to a blank slate on every open. Stale state —
  destination, amount, memo, and above all an armed "send all funds"
  toggle — silently carried into the next payment.
- Arming "send all funds" now shows the swept balance in the (disabled)
  amount field instead of a confusing 0; disarming or leaving the
  on-chain tab clears it.
- The scan modal no longer hides "Scan with camera" on plain-http desktop
  (browsers only allow getUserMedia on secure origins): the option stays
  visible with a one-line explanation, and choosing it surfaces the HTTPS
  requirement with photo/paste fallbacks. The companion app's native
  scanner path is untouched and still takes priority.
- What's New entry for v1.7.125-alpha.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/components/ReceiveBitcoinModal.vue

@@ -107,7 +107,21 @@ const props = defineProps<{
 const emit = defineEmits<{ close: []; received: []; scan: [] }>()
 
 watch(() => props.show, (open) => {
-  if (open && props.autoGenerate && receiveMethod.value === 'onchain' && !onchainAddress.value) {
+  if (!open) return
+  // Blank slate on every open: a leftover amount/memo/token or a previous
+  // invoice quietly carrying into a new receive flow is exactly the stale-
+  // state class the operator flagged on the send modal (2026-08-05).
+  receiveMethod.value = 'onchain'
+  invoiceAmount.value = 0
+  invoiceMemo.value = ''
+  invoiceResult.value = ''
+  onchainAddress.value = ''
+  arkAddress.value = ''
+  ecashToken.value = ''
+  ecashResult.value = ''
+  error.value = ''
+  processing.value = false
+  if (props.autoGenerate && receiveMethod.value === 'onchain') {
     void receive()
   }
 })