feat(group-chat): add ephemeral visual pass indicator when bot passes turn

- Display a subtle centered system pill '[⏩ {bot} passed]' when a bot passes
- Style with Material icon (Icons.Filled.FastForward) and surface tokens
- Keep pass indicators strictly ephemeral to avoid polluting LLM prompt context
- Exclude from cross-device snapshot sync so it disappears on restart/rehydrate
- Add English and Arabic localized string resources
- Update GroupChatViewModelTest to verify pass indicator presence and LLM filtering

Co-authored-by: Luna <luna.m57@agentmail.to>

app/src/test/java/com/m57/hermescontrol/ui/bots/group/GroupChatViewModelTest.kt

@@ -266,9 +266,17 @@ class GroupChatViewModelTest {
             testScheduler.runCurrent()
 
             val finalState = viewModel.uiState.value
-            // Only the user message should remain; (pass) is filtered out
-            assertEquals(1, finalState.messages.size)
+            // User message plus the visual pass indicator
+            assertEquals(2, finalState.messages.size)
             assertTrue(finalState.messages.first().isUser)
+            val passMsg = finalState.messages.last()
+            assertTrue(passMsg.isSystem)
+            assertTrue(passMsg.isPass)
+            assertEquals("Scout Bot", passMsg.senderDisplayName)
+            assertEquals("Scout Bot passed", passMsg.text)
+
+            // LLM prompt history only considers non-system messages
+            assertEquals(1, finalState.messages.filter { !it.isSystem }.size)
         }
 
     @Test