feat(KB-184): change autoMerge default from false to true

- Update DEFAULT_SETTINGS in core types to set autoMerge: true
- Update initial state defaults in App and SettingsModal components
- Update test fixtures in App, Board, and SettingsModal tests
- Update kb-board skill docs to reflect new default
- Add minor changeset for the default change

packages/dashboard/app/App.tsx

@@ -16,7 +16,7 @@ function AppInner() {
   const [settingsOpen, setSettingsOpen] = useState(false);
   const [settingsInitialSection, setSettingsInitialSection] = useState<SectionId | undefined>(undefined);
   const [maxConcurrent, setMaxConcurrent] = useState(2);
-  const [autoMerge, setAutoMerge] = useState(false);
+  const [autoMerge, setAutoMerge] = useState(true);
   const [globalPaused, setGlobalPaused] = useState(false);
   const [enginePaused, setEnginePaused] = useState(false);
   const { tasks, createTask, moveTask, deleteTask, mergeTask, retryTask } = useTasks();

packages/dashboard/app/components/SettingsModal.tsx

@@ -42,7 +42,7 @@ interface SettingsModalProps {
 }
 
 export function SettingsModal({ onClose, addToast, initialSection }: SettingsModalProps) {
-  const [form, setForm] = useState<Settings & { worktreeInitCommand?: string }>({ maxConcurrent: 2, maxWorktrees: 4, pollIntervalMs: 15000, groupOverlappingFiles: false, autoMerge: false, recycleWorktrees: false, includeTaskIdInCommit: true, worktreeInitCommand: "" });
+  const [form, setForm] = useState<Settings & { worktreeInitCommand?: string }>({ maxConcurrent: 2, maxWorktrees: 4, pollIntervalMs: 15000, groupOverlappingFiles: false, autoMerge: true, recycleWorktrees: false, includeTaskIdInCommit: true, worktreeInitCommand: "" });
   const [loading, setLoading] = useState(true);
   const [activeSection, setActiveSection] = useState<SectionId>(initialSection ?? SETTINGS_SECTIONS[0].id);
   const [prefixError, setPrefixError] = useState<string | null>(null);

packages/dashboard/app/components/__tests__/App.test.tsx

@@ -8,7 +8,7 @@ const defaultSettings: Settings = {
   maxWorktrees: 4,
   pollIntervalMs: 15000,
   groupOverlappingFiles: false,
-  autoMerge: false,
+  autoMerge: true,
   recycleWorktrees: false,
   worktreeInitCommand: "",
   testCommand: "",

packages/dashboard/app/components/__tests__/Board.test.tsx

@@ -25,7 +25,7 @@ function renderBoard() {
       onCancelCreate={noop}
       onCreateTask={noopAsync}
       onNewTask={noop}
-      autoMerge={false}
+      autoMerge={true}
       onToggleAutoMerge={noop}
       globalPaused={false}
     />,

packages/dashboard/app/components/__tests__/SettingsModal.test.tsx

@@ -8,7 +8,7 @@ const defaultSettings: Settings = {
   maxWorktrees: 4,
   pollIntervalMs: 15000,
   groupOverlappingFiles: false,
-  autoMerge: false,
+  autoMerge: true,
   recycleWorktrees: false,
   worktreeInitCommand: "",
   testCommand: "",