Add WeatherKit data source package

Implements @aris/data-source-weatherkit for fetching weather data from
Apple WeatherKit REST API.

- WeatherKitDataSource class implementing DataSource interface
- Feed items: current, hourly, daily, and alerts
- Priority adjustment based on weather conditions and alert severity
- Unit conversion (metric/imperial)
- Response validation with arktype
- Test fixtures from real API responses

Co-authored-by: Ona <no-reply@ona.com>

packages/aris-data-source-weatherkit/src/feed-items.ts

@@ -0,0 +1,97 @@
+import type { FeedItem } from "@aris/core"
+
+import type { Certainty, ConditionCode, PrecipitationType, Severity, Urgency } from "./weatherkit"
+
+export const WeatherFeedItemType = {
+	current: "weather-current",
+	hourly: "weather-hourly",
+	daily: "weather-daily",
+	alert: "weather-alert",
+} as const
+
+export type WeatherFeedItemType = (typeof WeatherFeedItemType)[keyof typeof WeatherFeedItemType]
+
+export type CurrentWeatherData = {
+	conditionCode: ConditionCode
+	daylight: boolean
+	humidity: number
+	precipitationIntensity: number
+	pressure: number
+	pressureTrend: "rising" | "falling" | "steady"
+	temperature: number
+	temperatureApparent: number
+	uvIndex: number
+	visibility: number
+	windDirection: number
+	windGust: number
+	windSpeed: number
+}
+
+export interface CurrentWeatherFeedItem extends FeedItem<
+	typeof WeatherFeedItemType.current,
+	CurrentWeatherData
+> {}
+
+export type HourlyWeatherData = {
+	forecastTime: Date
+	conditionCode: ConditionCode
+	daylight: boolean
+	humidity: number
+	precipitationAmount: number
+	precipitationChance: number
+	precipitationType: PrecipitationType
+	temperature: number
+	temperatureApparent: number
+	uvIndex: number
+	windDirection: number
+	windGust: number
+	windSpeed: number
+}
+
+export interface HourlyWeatherFeedItem extends FeedItem<
+	typeof WeatherFeedItemType.hourly,
+	HourlyWeatherData
+> {}
+
+export type DailyWeatherData = {
+	forecastDate: Date
+	conditionCode: ConditionCode
+	maxUvIndex: number
+	precipitationAmount: number
+	precipitationChance: number
+	precipitationType: PrecipitationType
+	snowfallAmount: number
+	sunrise: Date
+	sunset: Date
+	temperatureMax: number
+	temperatureMin: number
+}
+
+export interface DailyWeatherFeedItem extends FeedItem<
+	typeof WeatherFeedItemType.daily,
+	DailyWeatherData
+> {}
+
+export type WeatherAlertData = {
+	alertId: string
+	areaName: string
+	certainty: Certainty
+	description: string
+	detailsUrl: string
+	effectiveTime: Date
+	expireTime: Date
+	severity: Severity
+	source: string
+	urgency: Urgency
+}
+
+export interface WeatherAlertFeedItem extends FeedItem<
+	typeof WeatherFeedItemType.alert,
+	WeatherAlertData
+> {}
+
+export type WeatherFeedItem =
+	| CurrentWeatherFeedItem
+	| HourlyWeatherFeedItem
+	| DailyWeatherFeedItem
+	| WeatherAlertFeedItem