feat(ssr): previous calendar year period + external register filters

- P&L period dropdown: replace "Calendar year (YYYY)" with
  "Previous Calendar Year (YYYY-1)" pulling the full prior year
- External register: title now reads "External Register"; add
  Source, External Id, and Location filters

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

resources/public/js/htmx-disable.js

@@ -268,6 +268,21 @@ const  calendarYearPeriod = (date) => {
     return {end: formatDateMMDDYYYY(end), start: formatDateMMDDYYYY(start)};
 }
 
+const  previousCalendarYearPeriod = (date) => {
+    if (!date) {
+        date= new Date()
+    } else {
+        date = parseMMDDYYYY(date)
+    }
+    const priorYear = date.getFullYear() - 1;
+
+    // Jan 1 - Dec 31 of the previous calendar year
+    const start = new Date(priorYear, 0, 1);
+    const end = new Date(priorYear, 11, 31);
+
+    return {end: formatDateMMDDYYYY(end), start: formatDateMMDDYYYY(start)};
+}
+
 const getLastMonthPeriods = (date) => {
     if (!date) {
         date = new Date();