feat: add weather unit preferences

tests/weather-brief.test.ts

@@ -54,10 +54,16 @@ function warning(overrides: Partial<WeatherWarning> = {}): WeatherWarning {
 }
 
 describe("weather briefs", () => {
-  it("uses selected temperature and wind units in the morning brief", () => {
+  it("uses selected temperature, wind and precipitation units in the morning brief", () => {
     const brief = buildWeatherBrief({
       forecast: forecast([
-        hour({ time: "2026-06-14T08:00", temperature: 10, windSpeed: 4, precipitationProbability: 80 }),
+        hour({
+          time: "2026-06-14T08:00",
+          temperature: 10,
+          windSpeed: 4,
+          precipitationProbability: 80,
+          precipitation: 25.4,
+        }),
         hour({ time: "2026-06-14T09:00", temperature: 12, windSpeed: 5, precipitationProbability: 30 }),
       ]),
       warnings: [],
@@ -67,6 +73,7 @@ describe("weather briefs", () => {
       language: "en",
       temperatureUnit: "f",
       windSpeedUnit: "mph",
+      precipitationUnit: "in",
       now: new Date("2026-06-14T06:00:00.000Z"),
     });
 
@@ -74,25 +81,34 @@ describe("weather briefs", () => {
     expect(brief?.pushBody).toContain("50°F-54°F");
     expect(brief?.pushBody).toContain("wind 11 mph");
     expect(brief?.pushBody).not.toContain("km/h");
+    expect(brief?.body.join(" ")).toContain("1.00 in");
   });
 
   it("warns about tomorrow storms from model weather codes without IMGW warning", () => {
     const brief = buildTomorrowWeatherBrief({
       forecast: forecast([
         hour({ time: "2026-06-15T08:00", temperature: 14, weatherCode: 3, precipitationProbability: 20 }),
-        hour({ time: "2026-06-15T15:00", temperature: 21, weatherCode: 95, precipitationProbability: 30 }),
+        hour({
+          time: "2026-06-15T15:00",
+          temperature: 21,
+          weatherCode: 95,
+          precipitationProbability: 30,
+          precipitation: 25.4,
+        }),
       ]),
       warnings: [],
       province: "mazowieckie",
       countyTeryt: "1465",
       locationName: "Warsaw",
       language: "en",
+      precipitationUnit: "in",
       now: new Date("2026-06-14T16:00:00.000Z"),
     });
 
     expect(brief?.severity).toBe("warning");
     expect(brief?.headline).toBe("Thunderstorms are possible tomorrow");
     expect(brief?.pushBody).toContain("thunderstorms");
+    expect(brief?.pushBody).toContain("1.00 in");
     expect(brief?.pushBody).not.toContain("IMGW");
   });