ix: Fix rece condition when detecting the browser extension.

[RickyNotaro]

No description provided.

[Copilot]

Pull request overview

This PR addresses a race condition in production where API requests could be routed through the proxy fallback before the browser extension detection finished, by making requests wait for a single shared detection promise.

Changes:

• Replace per-call extension detection with a module-level detectionPromise that runs once in production.
• Make the production Axios request interceptor async and await extension detection before choosing direct vs corsproxy.io routing.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

fetch() can hang for a long time on some networks; since all production requests now await detectionPromise, this can stall every API call indefinitely. Consider adding an explicit timeout/AbortController (and treating timeout as “no extension”) so requests can proceed via the proxy fallback even if detection never completes.

Suggested change

	try {
	const resp = await fetch(
	`${TARGET_BASE}/WCF/LSI/LSIBookingServiceV3.svc/GetAvailableVehicles?BranchID=1&LanguageID=2`,
	{ method: 'HEAD', mode: 'cors' },
	);
	extensionDetected = resp.ok;
	} catch {
	extensionDetected = false;
	}
	detectionDone = true;
	// Ensure extension detection cannot hang indefinitely; treat timeout as "no extension".
	if (typeof AbortController === 'undefined') {
	// Fallback for environments without AbortController: behave as before (no explicit timeout).
	try {
	const resp = await fetch(
	`${TARGET_BASE}/WCF/LSI/LSIBookingServiceV3.svc/GetAvailableVehicles?BranchID=1&LanguageID=2`,
	{ method: 'HEAD', mode: 'cors' },
	);
	extensionDetected = resp.ok;
	} catch {
	extensionDetected = false;
	}
	detectionDone = true;
	return;
	}
	const controller = new AbortController();
	const timeoutId = setTimeout(() => controller.abort(), 5000);
	try {
	const resp = await fetch(
	`${TARGET_BASE}/WCF/LSI/LSIBookingServiceV3.svc/GetAvailableVehicles?BranchID=1&LanguageID=2`,
	{ method: 'HEAD', mode: 'cors', signal: controller.signal },
	);
	extensionDetected = resp.ok;
	} catch {
	// Network errors or aborts (including timeout) are treated as "no extension".
	extensionDetected = false;
	} finally {
	clearTimeout(timeoutId);
	detectionDone = true;
	}

[Copilot]

detectionPromise resolves to void and updates module-level state (extensionDetected/detectionDone). This makes it harder to reason about and requires the extra detectionDone flag. Consider making the promise resolve to the detected boolean (and/or always awaiting the same promise) to reduce shared mutable state and simplify the interceptor logic.