feat: add company holiday preference feature with UI and logic for holiday selection

public/js/state.js

@@ -22,6 +22,9 @@ let currentEntryId = null; // ID of today's entry being timed
 let displayYear = new Date().getFullYear();
 let displayMonth = new Date().getMonth(); // 0-11
 
+// Settings state
+let companyHolidayPreference = 'christmas'; // 'christmas' (24.12) or 'newyearseve' (31.12)
+
 // Bulk edit state
 let bulkEditMode = false;
 let selectedEntries = new Set();
@@ -44,6 +47,8 @@ function setCurrentEntryId(id) { currentEntryId = id; }
 function setDisplayYear(year) { displayYear = year; }
 function setDisplayMonth(month) { displayMonth = month; }
 
+function setCompanyHolidayPreference(preference) { companyHolidayPreference = preference; }
+
 function setBulkEditMode(mode) { bulkEditMode = mode; }
 function clearSelectedEntries() { selectedEntries.clear(); }
 function addSelectedEntry(id) { selectedEntries.add(id); }