fix: move BookingFlow window type to app.d.ts and fix authHeaders typing

Move __bookingFlowCountdownInterval from inline declare global in BookingFlow.svelte to global app.d.ts. Fix authHeaders type from {} to undefined to satisfy TypeScript.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/go.mod

@@ -54,7 +54,7 @@ require (
 	github.com/rogpeppe/go-internal v1.14.1 // indirect
 	github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd // indirect
 	github.com/valyala/fastjson v1.6.10 // indirect
-	golang.org/x/image v0.42.0 // indirect
+	golang.org/x/image v0.43.0 // indirect
 	golang.org/x/sync v0.21.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

backend/go.sum

@@ -128,6 +128,8 @@ golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
 golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
 golang.org/x/image v0.42.0 h1:1gSs6ehNWXLbkHBIPcWztk3D/6aIA/8hauiAYtlodVY=
 golang.org/x/image v0.42.0/go.mod h1:rrpelvGFt+kLPAjPM4HeWPgrl0FtafueU//e5N0qk/Q=
+golang.org/x/image v0.43.0 h1:FLxcP4ec2350nTfOC8ysKtqYSIFbk/QGjw1ZHNP4tsY=
+golang.org/x/image v0.43.0/go.mod h1:rrpelvGFt+kLPAjPM4HeWPgrl0FtafueU//e5N0qk/Q=
 golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
 golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=

frontend/src/app.d.ts

@@ -13,6 +13,7 @@ declare global {
 		__walkInCountdownInterval?: ReturnType<typeof setInterval>;
 		__walkInModalCountdownInterval?: ReturnType<typeof setInterval>;
 		__bookingCreateCountdownInterval?: ReturnType<typeof setInterval>;
+		__bookingFlowCountdownInterval?: ReturnType<typeof setInterval> | null;
 	}
 }
 

frontend/src/lib/components/booking/BookingFlow.svelte

@@ -27,12 +27,6 @@
 	import { onDestroy } from 'svelte';
 	import { SvelteDate } from 'svelte/reactivity';
 
-	declare global {
-		interface Window {
-			__bookingFlowCountdownInterval?: ReturnType<typeof setInterval> | null;
-		}
-	}
-
 	// Components
 	import BookingActions from '$lib/components/booking/BookingActions.svelte';
 	import BookingSummary from '$lib/components/booking/BookingSummary.svelte';
@@ -688,7 +682,7 @@
 		loadingAvailableHours = true;
 
 		try {
-			const authHeaders = authStore.currentToken ? { Authorization: `Bearer ${authStore.currentToken}` } : {};
+			const authHeaders: RequestInit['headers'] = authStore.currentToken ? { Authorization: `Bearer ${authStore.currentToken}` } : undefined;
 			const [whRes, ahRes] = await Promise.all([
 				fetch(`/api/scheduling/working-hours?start=${startStr}&end=${endStr}`, { headers: authHeaders }),
 				fetch(`/api/scheduling/available-hours?start=${startStr}&end=${endStr}`, { headers: authHeaders })
@@ -782,7 +776,7 @@
 			const startStr = startOfMonth.toString();
 			const endStr = endOfMonth.toString();
 
-			const authHeaders = authStore.currentToken ? { Authorization: `Bearer ${authStore.currentToken}` } : {};
+			const authHeaders: RequestInit['headers'] = authStore.currentToken ? { Authorization: `Bearer ${authStore.currentToken}` } : undefined;
 
 			// Fetch working hours
 			const workingHoursResponse = await fetch(