fix: derive createList append index from board detail

app/src/main/java/space/hackenslacker/kanbn4droid/app/boarddetail/BoardDetailRepository.kt

@@ -86,12 +86,23 @@ class BoardDetailRepository(
             is BoardsApiResult.Failure -> return sessionResult
         }
 
+        val appendIndex = when (
+            val boardDetailResult = apiClient.getBoardDetail(
+                baseUrl = session.baseUrl,
+                apiKey = session.apiKey,
+                boardId = normalizedBoardPublicId,
+            )
+        ) {
+            is BoardsApiResult.Success -> boardDetailResult.value.lists.size
+            is BoardsApiResult.Failure -> return BoardsApiResult.Failure(boardDetailResult.message)
+        }
+
         return apiClient.createList(
             baseUrl = session.baseUrl,
             apiKey = session.apiKey,
             boardPublicId = normalizedBoardPublicId,
             title = normalizedTitle,
-            appendIndex = 0,
+            appendIndex = appendIndex,
         )
     }
 

app/src/test/java/space/hackenslacker/kanbn4droid/app/boarddetail/BoardDetailRepositoryTest.kt

@@ -287,15 +287,43 @@ class BoardDetailRepositoryTest {
 
     @Test
     fun createListDelegatesToApiWithTrimmedIds() = runTest {
-        val apiClient = FakeBoardDetailApiClient()
+        val apiClient = FakeBoardDetailApiClient().apply {
+            boardDetailResult = BoardsApiResult.Success(
+                BoardDetail(
+                    id = "board-1",
+                    title = "Board",
+                    lists = listOf(
+                        BoardListDetail(id = "list-1", title = "One", cards = emptyList()),
+                        BoardListDetail(id = "list-2", title = "Two", cards = emptyList()),
+                        BoardListDetail(id = "list-3", title = "Three", cards = emptyList()),
+                    ),
+                ),
+            )
+        }
         val repository = createRepository(apiClient = apiClient)
 
         val result = repository.createList(boardPublicId = " board-1 ", title = " New List ")
 
         assertTrue(result is BoardsApiResult.Success<*>)
+        assertEquals("board-1", apiClient.lastBoardId)
         assertEquals("board-1", apiClient.lastCreateListBoardPublicId)
         assertEquals("New List", apiClient.lastCreateListTitle)
-        assertEquals(0, apiClient.lastCreateListAppendIndex)
+        assertEquals(3, apiClient.lastCreateListAppendIndex)
+    }
+
+    @Test
+    fun createListPropagatesFailureWhenBoardDetailPrefetchFails() = runTest {
+        val apiClient = FakeBoardDetailApiClient().apply {
+            boardDetailResult = BoardsApiResult.Failure("Cannot load board")
+        }
+        val repository = createRepository(apiClient = apiClient)
+
+        val result = repository.createList(boardPublicId = "board-1", title = "New List")
+
+        assertTrue(result is BoardsApiResult.Failure)
+        assertEquals("Cannot load board", (result as BoardsApiResult.Failure).message)
+        assertEquals("board-1", apiClient.lastBoardId)
+        assertEquals(null, apiClient.lastCreateListBoardPublicId)
     }
 
     @Test