fix(sse): scope dispose to per-screen provider instance

modules/ensemble/lib/framework/apiproviders/api_provider.dart

@@ -31,7 +31,7 @@ class APIProviders extends InheritedWidget {
     } else if (provider == 'firebaseFunction') {
       return FirebaseFunctionsAPIProvider();
     } else if (provider == 'sse') {
-      return SSEAPIProvider();
+      return providers[provider] ?? SSEAPIProvider();
     } else {
       return providers[provider] ?? httpProvider;
     }

modules/ensemble/lib/framework/apiproviders/sse_api_provider.dart

@@ -24,9 +24,9 @@ import 'package:crypto/crypto.dart';
 /// Server-Sent Events (SSE) API Provider
 /// Handles streaming HTTP connections
 class SSEAPIProvider extends APIProvider with LiveAPIProvider {
-  static final Map<String, StreamSubscription> _subscriptions = {};
-  static final Map<String, http.Client> _activeClients = {};
-  static final Set<String> _manuallyDisconnected = {};
+  final Map<String, StreamSubscription> _subscriptions = {};
+  final Map<String, http.Client> _activeClients = {};
+  final Set<String> _manuallyDisconnected = {};
 
   @override
   Future<void> init(String appId, Map<String, dynamic> config) async {
@@ -530,22 +530,30 @@ class SSEAPIProvider extends APIProvider with LiveAPIProvider {
 
   @override
   dispose() {
-    _manuallyDisconnected.addAll(_subscriptions.keys);
+    for (final apiName in _subscriptions.keys.toList()) {
+      _manuallyDisconnected.add(apiName);
+    }
 
-    // Cancel all subscriptions
-    for (var subscription in _subscriptions.values) {
+    for (final subscription in _subscriptions.values) {
       subscription.cancel();
     }
     _subscriptions.clear();
 
-    // Close all active clients
-    for (var client in _activeClients.values) {
+    for (final client in _activeClients.values) {
       client.close();
     }
     _activeClients.clear();
 
     _manuallyDisconnected.clear();
   }
+
+  @visibleForTesting
+  int get subscriptionCountForTesting => _subscriptions.length;
+
+  @visibleForTesting
+  void trackSubscriptionForTesting(String apiName, StreamSubscription sub) {
+    _subscriptions[apiName] = sub;
+  }
 }
 
 /// Configuration options for SSE connections

modules/ensemble/test/sse_provider_dispose_test.dart

@@ -0,0 +1,52 @@
+import 'dart:async';
+
+import 'package:ensemble/framework/apiproviders/api_provider.dart';
+import 'package:ensemble/framework/apiproviders/http_api_provider.dart';
+import 'package:ensemble/framework/apiproviders/sse_api_provider.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('SSEAPIProvider.dispose', () {
+    test('cancels only this instance subscriptions', () async {
+      final providerA = SSEAPIProvider();
+      final providerB = SSEAPIProvider();
+
+      var aCanceled = false;
+      var bCanceled = false;
+      final controllerA = StreamController<int>(onCancel: () => aCanceled = true);
+      final controllerB = StreamController<int>(onCancel: () => bCanceled = true);
+
+      providerA.trackSubscriptionForTesting(
+        'liveFeed',
+        controllerA.stream.listen((_) {}),
+      );
+      providerB.trackSubscriptionForTesting(
+        'metrics',
+        controllerB.stream.listen((_) {}),
+      );
+
+      providerA.dispose();
+
+      expect(providerA.subscriptionCountForTesting, 0);
+      expect(providerB.subscriptionCountForTesting, 1);
+      expect(aCanceled, isTrue);
+      expect(bCanceled, isFalse);
+
+      await controllerA.close();
+      await controllerB.close();
+    });
+  });
+
+  group('APIProviders.getProvider', () {
+    test('returns cloned sse provider from screen map', () {
+      final sse = SSEAPIProvider();
+      final providers = APIProviders(
+        providers: {'sse': sse, 'http': HTTPAPIProvider()},
+        child: const SizedBox.shrink(),
+      );
+
+      expect(identical(providers.getProvider('sse'), sse), isTrue);
+    });
+  });
+}