feat: enhance error handling with PostHog integration

- Added PostHog error capturing for non-authentication errors in BaseApiService.
- Refactored PostHog client initialization to ensure a single instance is used across the application.

surfsense_web/lib/apis/base-api.service.ts

@@ -1,3 +1,4 @@
+import posthog from "posthog-js";
 import type { ZodType } from "zod";
 import { getBearerToken, handleUnauthorized, refreshAccessToken } from "../auth-utils";
 import { AppError, AuthenticationError, AuthorizationError, NotFoundError } from "../error";
@@ -231,6 +232,20 @@ class BaseApiService {
 			return data;
 		} catch (error) {
 			console.error("Request failed:", JSON.stringify(error));
+			if (!(error instanceof AuthenticationError)) {
+				try {
+					posthog.captureException(error, {
+						api_url: url,
+						api_method: options?.method ?? "GET",
+						...(error instanceof AppError && {
+							status_code: error.status,
+							status_text: error.statusText,
+						}),
+					});
+				} catch {
+					// PostHog capture failed — don't block the error flow
+				}
+			}
 			throw error;
 		}
 	}

surfsense_web/lib/posthog/server.ts

@@ -1,17 +1,19 @@
 import { PostHog } from "posthog-node";
 
+let posthogInstance: PostHog | null = null;
+
 export default function PostHogClient() {
 	if (!process.env.NEXT_PUBLIC_POSTHOG_KEY) {
 		throw new Error("NEXT_PUBLIC_POSTHOG_KEY is not set");
 	}
 
-	const posthogClient = new PostHog(process.env.NEXT_PUBLIC_POSTHOG_KEY, {
-		host: process.env.NEXT_PUBLIC_POSTHOG_HOST,
-		// Because server-side functions in Next.js can be short-lived,
-		// we set flushAt to 1 and flushInterval to 0 to ensure events are sent immediately
-		flushAt: 1,
-		flushInterval: 0,
-	});
+	if (!posthogInstance) {
+		posthogInstance = new PostHog(process.env.NEXT_PUBLIC_POSTHOG_KEY, {
+			host: process.env.NEXT_PUBLIC_POSTHOG_HOST,
+			flushAt: 1,
+			flushInterval: 0,
+		});
+	}
 
-	return posthogClient;
+	return posthogInstance;
 }