Fix settlement linking to original expense/receivable entries

The frontend now:
1. Fetches unsettled entries when opening settlement dialogs
2. Includes entry links (exp-xxx/rcv-xxx) in settlement payloads
3. Passes settled_entry_links to backend for proper linking

This enables the settlement transaction to include links back to
the original entries it is settling, making it possible to track
which expenses/receivables have been paid.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

static/js/index.js

@@ -1137,7 +1137,7 @@ window.app = Vue.createApp({
       this.receivableDialog.reference = ''
       this.receivableDialog.currency = null
     },
-    showSettleReceivableDialog(userBalance) {
+    async showSettleReceivableDialog(userBalance) {
       // Only show for users who owe castle (positive balance = receivable)
       if (userBalance.balance <= 0) return
 
@@ -1151,6 +1151,19 @@ window.app = Vue.createApp({
       const fiatCurrency = Object.keys(fiatBalances)[0] || null // Get first fiat currency (e.g., 'EUR')
       const fiatAmount = fiatCurrency ? Math.abs(fiatBalances[fiatCurrency]) : 0
 
+      // Fetch unsettled receivable entries for this user
+      let unsettledEntries = []
+      try {
+        const response = await LNbits.api.request(
+          'GET',
+          `/castle/api/v1/users/${userBalance.user_id}/unsettled-entries?entry_type=receivable`,
+          this.g.user.wallets[0].adminkey
+        )
+        unsettledEntries = response.data.unsettled_entries || []
+      } catch (error) {
+        console.warn('Could not fetch unsettled entries:', error)
+      }
+
       this.settleReceivableDialog = {
         show: true,
         user_id: userBalance.user_id,
@@ -1168,7 +1181,9 @@ window.app = Vue.createApp({
         checkWalletKey: null,
         pollIntervalId: null,
         exchangeRate: fiatAmount > 0 ? Math.abs(userBalance.balance) / fiatAmount : this.currentExchangeRate, // Calculate rate from actual amounts or use current rate
-        originalCurrency: fiatCurrency || 'BTC'
+        originalCurrency: fiatCurrency || 'BTC',
+        unsettledEntries: unsettledEntries, // Store for linking in settlement
+        entryLinks: unsettledEntries.map(e => e.link).filter(l => l) // Extract rcv-xxx links
       }
     },
     async generateSettlementInvoice() {
@@ -1304,6 +1319,11 @@ window.app = Vue.createApp({
           payload.amount_sats = this.settleReceivableDialog.maxAmount
         }
 
+        // Include links to entries being settled
+        if (this.settleReceivableDialog.entryLinks && this.settleReceivableDialog.entryLinks.length > 0) {
+          payload.settled_entry_links = this.settleReceivableDialog.entryLinks
+        }
+
         const response = await LNbits.api.request(
           'POST',
           '/castle/api/v1/receivables/settle',
@@ -1329,7 +1349,7 @@ window.app = Vue.createApp({
         this.settleReceivableDialog.loading = false
       }
     },
-    showPayUserDialog(userBalance) {
+    async showPayUserDialog(userBalance) {
       // Only show for users castle owes (negative balance = payable)
       if (userBalance.balance >= 0) return
 
@@ -1342,6 +1362,19 @@ window.app = Vue.createApp({
       const maxAmountSats = Math.abs(userBalance.balance)
       const maxAmountFiat = Math.abs(fiatAmount)
 
+      // Fetch unsettled expense entries for this user
+      let unsettledEntries = []
+      try {
+        const response = await LNbits.api.request(
+          'GET',
+          `/castle/api/v1/users/${userBalance.user_id}/unsettled-entries?entry_type=expense`,
+          this.g.user.wallets[0].adminkey
+        )
+        unsettledEntries = response.data.unsettled_entries || []
+      } catch (error) {
+        console.warn('Could not fetch unsettled entries:', error)
+      }
+
       this.payUserDialog = {
         show: true,
         user_id: userBalance.user_id,
@@ -1356,7 +1389,9 @@ window.app = Vue.createApp({
         loading: false,
         paymentSuccess: false,
         exchangeRate: maxAmountFiat > 0 ? maxAmountSats / maxAmountFiat : this.currentExchangeRate,
-        originalCurrency: fiatCurrency || 'BTC'
+        originalCurrency: fiatCurrency || 'BTC',
+        unsettledEntries: unsettledEntries, // Store for linking in settlement
+        entryLinks: unsettledEntries.map(e => e.link).filter(l => l) // Extract exp-xxx links
       }
     },
     async sendLightningPayment() {
@@ -1395,16 +1430,23 @@ window.app = Vue.createApp({
         )
 
         // Record the payment in Castle accounting
+        const payPayload = {
+          user_id: this.payUserDialog.user_id,
+          amount: this.payUserDialog.amount,
+          payment_method: 'lightning',
+          payment_hash: paymentResponse.data.payment_hash
+        }
+
+        // Include links to entries being settled
+        if (this.payUserDialog.entryLinks && this.payUserDialog.entryLinks.length > 0) {
+          payPayload.settled_entry_links = this.payUserDialog.entryLinks
+        }
+
         await LNbits.api.request(
           'POST',
           '/castle/api/v1/payables/pay',
           this.g.user.wallets[0].adminkey,
-          {
+          payPayload
-            user_id: this.payUserDialog.user_id,
-            amount: this.payUserDialog.amount,
-            payment_method: 'lightning',
-            payment_hash: paymentResponse.data.payment_hash
-          }
         )
 
         this.payUserDialog.paymentSuccess = true
@@ -1461,6 +1503,11 @@ window.app = Vue.createApp({
           payload.amount_sats = this.payUserDialog.maxAmount
         }
 
+        // Include links to entries being settled
+        if (this.payUserDialog.entryLinks && this.payUserDialog.entryLinks.length > 0) {
+          payload.settled_entry_links = this.payUserDialog.entryLinks
+        }
+
         const response = await LNbits.api.request(
           'POST',
           '/castle/api/v1/payables/pay',