feat(auth): koppla login/register till Firebase → /v1/auth/session (AUTH-5)

apps/mobile/src/app/(auth)/login.tsx

@@ -2,6 +2,7 @@ import { useState } from "react";
 import { Text, View } from "react-native";
 import { Link, Redirect, router } from "expo-router";
 import { api } from "@/lib/api";
+import { firebaseAuthProvider } from "@/lib/auth-provider/firebase";
 import { useAuth, type AuthUser } from "@/lib/auth";
 import { t } from "@/lib/i18n";
 import { Body, Button, Input, Screen, Spacer, Title } from "@/components/ui";
@@ -27,9 +28,12 @@ export default function LoginScreen() {
     setBusy(true);
     setError(null);
     try {
-      const result = await api<LoginResponse>("/v1/auth/login", {
+      await firebaseAuthProvider.signInWithEmail(email.trim(), password);
+      const idToken = await firebaseAuthProvider.getIdToken();
+      if (!idToken) throw new Error(t("common.error"));
+      const result = await api<LoginResponse>("/v1/auth/session", {
         method: "POST",
-        body: { email, password },
+        body: { idToken },
       });
       await setSession(
         { accessToken: result.accessToken, refreshToken: result.refreshToken },

apps/mobile/src/app/(auth)/register.tsx

@@ -2,6 +2,7 @@ import { useState } from "react";
 import { Text, View } from "react-native";
 import { Link, router } from "expo-router";
 import { api } from "@/lib/api";
+import { firebaseAuthProvider } from "@/lib/auth-provider/firebase";
 import { persistLanguageTag, useAuth, type AuthUser } from "@/lib/auth";
 import { detectDeviceLanguageTag, t } from "@/lib/i18n";
 import { localeDefaultsForRegion } from "@app/shared-types";
@@ -28,13 +29,15 @@ export default function RegisterScreen() {
     setBusy(true);
     setError(null);
     try {
-      const result = await api<RegisterResponse>("/v1/auth/register", {
+      await firebaseAuthProvider.signUpWithEmail(email.trim(), password);
+      const idToken = await firebaseAuthProvider.getIdToken();
+      if (!idToken) throw new Error(t("common.error"));
+      const result = await api<RegisterResponse>("/v1/auth/session", {
         method: "POST",
         body: {
+          idToken,
           displayName,
-          email,
-          password,
-          // D-031: enhetens språk – backend skapar locale-preferenser före välkomstmejlet.
+          // D-031: enhetens språk – backend skapar locale-preferenser.
           locale: detectDeviceLanguageTag() ?? "sv-SE",
         },
       });