Stores and retrieves entry line metadata as JSON

Updates journal entry creation to store entry line metadata as a JSON string in the database.

Updates entry line retrieval to parse the JSON string back into a metadata object.

This change allows storing more complex data structures in the metadata field.

static/js/index.js

@@ -39,12 +39,10 @@ window.app = Vue.createApp({
       return 'Amount (sats) *'
     },
     currencyOptions() {
-      console.log('Computing currencyOptions, this.currencies:', this.currencies)
       const options = [{label: 'Satoshis (default)', value: null}]
       this.currencies.forEach(curr => {
         options.push({label: curr, value: curr})
       })
-      console.log('Currency options:', options)
       return options
     }
   },
@@ -92,12 +90,8 @@ window.app = Vue.createApp({
           '/castle/api/v1/currencies',
           this.g.user.wallets[0].inkey
         )
-        console.log('Currencies API response:', response)
-        console.log('Currencies data:', response.data)
         this.currencies = response.data
-        console.log('this.currencies:', this.currencies)
       } catch (error) {
-        console.error('Error loading currencies:', error)
         LNbits.utils.notifyApiError(error)
       }
     },