feat: avoid requiring window for the observability plugins (#135)

## Summary

Check for window availability in plugins.

## How did you test this change?

CI
<img width="828" height="451" alt="image"
src="https://github.com/user-attachments/assets/17caef38-7a70-42cf-9dcd-16accdd6641c"
/>
<img width="1671" height="655" alt="Screenshot 2025-07-21 at 12 08 06"
src="https://github.com/user-attachments/assets/fa69c606-1ff5-4651-8c47-f824803f5da8"
/>


## Are there any deployment considerations?

changeset

Author: Vadman97

.changeset/better-hotels-jog.md

@@ -0,0 +1,7 @@
+---
+'highlight.run': patch
+'@launchdarkly/observability': patch
+'@launchdarkly/session-replay': patch
+---
+
+conditionally check for window api availability

sdk/highlight-run/src/client/utils/storage.ts

@@ -66,6 +66,10 @@ export const getPersistentStorage = () => {
 		| typeof window.sessionStorage
 		| null = null
 
+	if (typeof window === 'undefined') {
+		return globalStorage
+	}
+
 	try {
 		switch (mode) {
 			case 'localStorage':
@@ -167,6 +171,12 @@ export const monkeyPatchLocalStorage = (
 		)
 		return
 	}
+	if (typeof window === 'undefined') {
+		console.warn(
+			`highlight.io cannot use local storage (not a window); segment integration will not work`,
+		)
+		return
+	}
 
 	const originalSetItem = window.localStorage.setItem
 	window.localStorage.setItem = function () {