feat: initialize project structure with core components and pages

- Added shared styles for UI components in `src/components/styles.ts`.
- Created configuration constants in `src/lib/config.ts`.
- Implemented date formatting and greeting functions in `src/lib/dates.ts` and corresponding tests in `src/lib/dates.test.ts`.
- Developed incident management functions in `src/lib/incidents.ts` with tests in `src/lib/incidents.test.ts`.
- Established navigation structure in `src/lib/navigation.ts`.
- Seeded demo data for incidents and users in `src/lib/seed.ts`.
- Defined tone classes for UI elements in `src/lib/tones.ts`.
- Created type definitions for incidents and related entities in `src/lib/types.ts`.
- Set up main application entry point in `src/main.tsx`.
- Developed various pages including About, Analytics, Incidents, Locations, Overview, and Report Incident.
- Configured testing setup in `src/test/setup.ts` and TypeScript configurations.
- Integrated Vite for development and testing with appropriate plugins.

src/lib/dates.ts

@@ -0,0 +1,24 @@
+const displayDate = new Intl.DateTimeFormat('en-US', { month: 'short', day: 'numeric', year: 'numeric', timeZone: 'UTC' })
+const longDate = new Intl.DateTimeFormat('en-US', { weekday: 'long', month: 'long', day: 'numeric', year: 'numeric' })
+
+/** Formats an ISO calendar date (`2024-08-28`) as `Aug 28, 2024`. */
+export function formatDate(isoDate: string): string {
+  return displayDate.format(new Date(`${isoDate}T00:00:00Z`))
+}
+
+/** Today's date in the viewer's local time zone as an ISO calendar date. */
+export function toIsoDate(date: Date): string {
+  const pad = (value: number) => String(value).padStart(2, '0')
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())}`
+}
+
+export function formatLongDate(date: Date): string {
+  return longDate.format(date)
+}
+
+export function greeting(date: Date): string {
+  const hour = date.getHours()
+  if (hour < 12) return 'Good morning'
+  if (hour < 18) return 'Good afternoon'
+  return 'Good evening'
+}