fix(permissions): Use react-permission capability per migration guide

- Add REACT_PERMISSION feature to SpreedFeatures enum
- Update hasReactPermission() to check react-permission capability first
- Fall back to chat-permission/CHAT bit for older servers
- Expand unit tests for all capability scenarios

Author: luflow

app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt

@@ -62,7 +62,8 @@ enum class SpreedFeatures(val value: String) {
     SENSITIVE_CONVERSATIONS("sensitive-conversations"),
     IMPORTANT_CONVERSATIONS("important-conversations"),
     THREADS("threads"),
-    PINNED_MESSAGES("pinned-messages")
+    PINNED_MESSAGES("pinned-messages"),
+    REACT_PERMISSION("react-permission")
 }
 
 @Suppress("TooManyFunctions")

app/src/main/java/com/nextcloud/talk/utils/ParticipantPermissions.kt

@@ -72,11 +72,14 @@ class ParticipantPermissions(
     }
 
     fun hasReactPermission(): Boolean {
+        if (CapabilitiesUtil.hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.REACT_PERMISSION)) {
+            // Server supports separate react permission - check REACT bit
+            return hasReactPermission
+        }
         if (CapabilitiesUtil.hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.CHAT_PERMISSION)) {
-            // Server supports granular permissions - check REACT bit
-            // Fall back to CHAT permission for backward compatibility with servers
-            // that have chat-permission capability but not yet the REACT permission split
-            return hasReactPermission || hasChatPermission
+            // Older server without react-permission capability - fall back to CHAT permission
+            // as that's what controlled reactions before the split
+            return hasChatPermission
         }
         // if capability is not available then the spreed version doesn't support to restrict this
         return true

app/src/test/java/com/nextcloud/talk/utils/ParticipantPermissionsTest.kt

@@ -48,11 +48,12 @@ class ParticipantPermissionsTest : TestCase() {
     }
 
     @Test
-    fun test_reactPermissionSet() {
+    fun test_reactPermissionWithReactCapability() {
         val spreedCapability = SpreedCapability()
-        spreedCapability.features = listOf("chat-permission")
+        spreedCapability.features = listOf("react-permission")
         val conversation = createConversation()
 
+        // With react-permission capability, only REACT bit matters
         conversation.permissions = ParticipantPermissions.REACT or
             ParticipantPermissions.CUSTOM
 
@@ -70,12 +71,36 @@ class ParticipantPermissionsTest : TestCase() {
     }
 
     @Test
-    fun test_reactPermissionFallbackToChat() {
+    fun test_reactPermissionDeniedWithReactCapability() {
+        val spreedCapability = SpreedCapability()
+        spreedCapability.features = listOf("react-permission")
+        val conversation = createConversation()
+
+        // With react-permission capability, only CHAT but no REACT - should NOT allow reactions
+        conversation.permissions = ParticipantPermissions.CHAT or
+            ParticipantPermissions.CUSTOM
+
+        val user = User()
+        user.id = 1
+
+        val attendeePermissions =
+            ParticipantPermissions(
+                spreedCapability,
+                ConversationModel.mapToConversationModel(conversation, user)
+            )
+
+        assertFalse(attendeePermissions.hasReactPermission())
+        assertTrue(attendeePermissions.hasChatPermission())
+    }
+
+    @Test
+    fun test_reactPermissionFallbackToChatOnOlderServer() {
         val spreedCapability = SpreedCapability()
+        // Older server without react-permission capability but with chat-permission
         spreedCapability.features = listOf("chat-permission")
         val conversation = createConversation()
 
-        // Only CHAT permission set, no REACT - should still allow reactions for backward compatibility
+        // Only CHAT permission set - should allow reactions as fallback for older servers
         conversation.permissions = ParticipantPermissions.CHAT or
             ParticipantPermissions.CUSTOM
 
@@ -92,6 +117,29 @@ class ParticipantPermissionsTest : TestCase() {
         assertTrue(attendeePermissions.hasChatPermission())
     }
 
+    @Test
+    fun test_reactPermissionDeniedOnOlderServerWithoutChatPermission() {
+        val spreedCapability = SpreedCapability()
+        // Older server without react-permission capability but with chat-permission
+        spreedCapability.features = listOf("chat-permission")
+        val conversation = createConversation()
+
+        // No CHAT permission - should deny reactions on older servers
+        conversation.permissions = ParticipantPermissions.CUSTOM
+
+        val user = User()
+        user.id = 1
+
+        val attendeePermissions =
+            ParticipantPermissions(
+                spreedCapability,
+                ConversationModel.mapToConversationModel(conversation, user)
+            )
+
+        assertFalse(attendeePermissions.hasReactPermission())
+        assertFalse(attendeePermissions.hasChatPermission())
+    }
+
     private fun createConversation() =
         Conversation(
             token = "test",