Adds resource scheduling and unavailability tracking

Introduces comprehensive schedule management for resources:
- Adds DateService with advanced time and date utilities
- Implements ResourceScheduleService for managing work hours
- Creates ScheduleRenderer to visualize unavailable time zones
- Extends resource model to support default weekly schedules

Enables granular tracking of resource availability and working hours

src/v2/core/DateService.ts

@@ -1,8 +1,20 @@
 import dayjs from 'dayjs';
+import utc from 'dayjs/plugin/utc';
+import timezone from 'dayjs/plugin/timezone';
+import isoWeek from 'dayjs/plugin/isoWeek';
 import { ITimeFormatConfig } from './ITimeFormatConfig';
 
+// Enable dayjs plugins
+dayjs.extend(utc);
+dayjs.extend(timezone);
+dayjs.extend(isoWeek);
+
 export class DateService {
-  constructor(private config: ITimeFormatConfig) {}
+  private timezone: string;
+
+  constructor(private config: ITimeFormatConfig) {
+    this.timezone = config.timezone;
+  }
 
   parseISO(isoString: string): Date {
     return dayjs(isoString).toDate();
@@ -18,4 +30,74 @@ export class DateService {
       monday.add(i, 'day').format('YYYY-MM-DD')
     );
   }
+
+  // ============================================
+  // FORMATTING
+  // ============================================
+
+  formatTime(date: Date, showSeconds = false): string {
+    const pattern = showSeconds ? 'HH:mm:ss' : 'HH:mm';
+    return dayjs(date).format(pattern);
+  }
+
+  formatTimeRange(start: Date, end: Date): string {
+    return `${this.formatTime(start)} - ${this.formatTime(end)}`;
+  }
+
+  formatDate(date: Date): string {
+    return dayjs(date).format('YYYY-MM-DD');
+  }
+
+  getDateKey(date: Date): string {
+    return this.formatDate(date);
+  }
+
+  // ============================================
+  // TIME CALCULATIONS
+  // ============================================
+
+  timeToMinutes(timeString: string): number {
+    const parts = timeString.split(':').map(Number);
+    const hours = parts[0] || 0;
+    const minutes = parts[1] || 0;
+    return hours * 60 + minutes;
+  }
+
+  minutesToTime(totalMinutes: number): string {
+    const hours = Math.floor(totalMinutes / 60);
+    const minutes = totalMinutes % 60;
+    return dayjs().hour(hours).minute(minutes).format('HH:mm');
+  }
+
+  getMinutesSinceMidnight(date: Date): number {
+    const d = dayjs(date);
+    return d.hour() * 60 + d.minute();
+  }
+
+  // ============================================
+  // UTC CONVERSIONS
+  // ============================================
+
+  toUTC(localDate: Date): string {
+    return dayjs.tz(localDate, this.timezone).utc().toISOString();
+  }
+
+  fromUTC(utcString: string): Date {
+    return dayjs.utc(utcString).tz(this.timezone).toDate();
+  }
+
+  // ============================================
+  // DATE CREATION
+  // ============================================
+
+  createDateAtTime(baseDate: Date | string, timeString: string): Date {
+    const totalMinutes = this.timeToMinutes(timeString);
+    const hours = Math.floor(totalMinutes / 60);
+    const minutes = totalMinutes % 60;
+    return dayjs(baseDate).startOf('day').hour(hours).minute(minutes).toDate();
+  }
+
+  getISOWeekDay(date: Date | string): number {
+    return dayjs(date).isoWeekday();  // 1=Monday, 7=Sunday
+  }
 }