fix: add temp_unit and timezone to inline BriefingConfig literals

BriefingSetupWizard and SettingsView had hardcoded initial objects that
predated the new fields, causing TS2345 type errors.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/BriefingSetupWizard.vue

@@ -19,6 +19,8 @@ const config = reactive<BriefingConfig>({
   work_days: [1, 2, 3, 4, 5],
   slots: { compilation: true, morning: true, midday: false, afternoon: false },
   notifications: true,
+  temp_unit: 'C',
+  timezone: '',
 })
 
 // Step 2 — locations

frontend/src/views/SettingsView.vue

@@ -126,6 +126,8 @@ const briefingConfig = ref<BriefingConfig>({
   work_days: [1, 2, 3, 4, 5],
   slots: { compilation: true, morning: true, midday: false, afternoon: false },
   notifications: true,
+  temp_unit: 'C',
+  timezone: '',
 });
 const briefingFeeds = ref<BriefingFeed[]>([]);
 const briefingSaving = ref(false);