Fix LNbits 1.4 compatibility: add null guards for g.user.wallets

LNbits 1.4 changed g.user initialization (PR #3615), moving it from
windowMixin to base.html. This means g.user can be null during initial
Vue template evaluation.

- Use optional chaining g.user?.wallets || [] in template
- Add null guard before accessing this.g.user.wallets in JS

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

static/js/index.js

@@ -181,13 +181,13 @@ window.app = Vue.createApp({
         this.lamassuConfig = data
 
         // When opening config dialog, populate the selected wallets if they exist
-        if (data && data.source_wallet_id) {
+        if (data && data.source_wallet_id && this.g.user?.wallets) {
           const wallet = this.g.user.wallets.find(w => w.id === data.source_wallet_id)
           if (wallet) {
             this.configDialog.data.selectedWallet = wallet
           }
         }
-        if (data && data.commission_wallet_id) {
+        if (data && data.commission_wallet_id && this.g.user?.wallets) {
           const commissionWallet = this.g.user.wallets.find(w => w.id === data.commission_wallet_id)
           if (commissionWallet) {
             this.configDialog.data.selectedCommissionWallet = commissionWallet

templates/satmachineadmin/index.html

@@ -547,7 +547,7 @@
         <q-select
           filled
           dense
-          :options="g.user.wallets"
+          :options="g.user?.wallets || []"
           v-model="configDialog.data.selectedWallet"
           label="Source Wallet for DCA Distributions *"
           option-label="name"
@@ -557,7 +557,7 @@
         <q-select
           filled
           dense
-          :options="g.user.wallets"
+          :options="g.user?.wallets || []"
           v-model="configDialog.data.selectedCommissionWallet"
           label="Commission Wallet (Optional)"
           option-label="name"