refactor: code clean up

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

src/types/date.ts

@@ -0,0 +1,4 @@
+export interface EpochSpan {
+  start: number;
+  end: number;
+}

src/types/index.ts

@@ -7,12 +7,6 @@
 // Local UI-specific types
 export type CalendarView = 'days' | 'month' | 'agenda';
 
-/** Half-open local calendar range: [startMs, endMs). */
-export interface VisibleDateRange {
-  startMs: number;
-  endMs: number;
-}
-
 export interface ViewState {
   currentView: CalendarView;
   currentDate: Date;

src/types/instance.ts

@@ -4,10 +4,10 @@ export interface CalendarInstance {
   key: string
   entity: EntityObject
   instanceId: string | null
-  startMs: number
-  endMs: number
-  dayStartMs: number
-  durationMs: number
+  start: number
+  end: number
+  dayStart: number
+  duration: number
   timeless: boolean
   multiDay: boolean
   label: string | null