feat: add "+ new tab" option to move window menu (#229)

* feat: add "+ new tab" option to move window menu

Adds a "+ New tab" option at the top of the "Move to tab" submenu in the
window toolbar. This allows users to create a new tab and move the current
window to it in a single action, streamlining the workflow.

Changes:
- Add moveWindowToNewWorkspace function in logic.ts
- Expose moveWindowToNewWorkspace through useGrimoire hook
- Always show "Move to tab" menu (not just when multiple tabs exist)
- Add "+ New tab" option with Plus icon at top of submenu

https://claude.ai/code/session_01Hy2vYBooPyrF7ZJCodcCav

* refactor: simplify new tab menu item copy

- Change menu text from "+ New tab" to "New" (icon already shows +)
- Simplify toast to just "Moved to new tab"

https://claude.ai/code/session_01Hy2vYBooPyrF7ZJCodcCav

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/core/logic.ts

@@ -227,6 +227,52 @@ export const moveWindowToWorkspace = (
   };
 };
 
+/**
+ * Creates a new workspace and moves a window to it.
+ * Returns an object with the new state and the new workspace ID.
+ */
+export const moveWindowToNewWorkspace = (
+  state: GrimoireState,
+  windowId: string,
+): { state: GrimoireState; newWorkspaceId: string } => {
+  const currentId = state.activeWorkspaceId;
+  const currentWs = state.workspaces[currentId];
+
+  // Find next available workspace number
+  const nextNumber = findLowestAvailableWorkspaceNumber(state.workspaces);
+
+  // Create new workspace ID
+  const newWorkspaceId = uuidv4();
+
+  // Remove window from current workspace
+  const newCurrentLayout = removeFromLayout(currentWs.layout, windowId);
+  const newCurrentWindowIds = currentWs.windowIds.filter(
+    (id) => id !== windowId,
+  );
+
+  // Create new state with new workspace and moved window
+  const newState: GrimoireState = {
+    ...state,
+    activeWorkspaceId: newWorkspaceId,
+    workspaces: {
+      ...state.workspaces,
+      [currentId]: {
+        ...currentWs,
+        layout: newCurrentLayout,
+        windowIds: newCurrentWindowIds,
+      },
+      [newWorkspaceId]: {
+        id: newWorkspaceId,
+        number: nextNumber,
+        layout: windowId,
+        windowIds: [windowId],
+      },
+    },
+  };
+
+  return { state: newState, newWorkspaceId };
+};
+
 export const updateLayout = (
   state: GrimoireState,
   layout: MosaicNode<string> | null,

src/core/state.ts

@@ -236,6 +236,20 @@ export const useGrimoire = () => {
     [setState],
   );
 
+  const moveWindowToNewWorkspace = useCallback(
+    (windowId: string): number => {
+      let newWorkspaceNumber = 0;
+      setState((prev) => {
+        const result = Logic.moveWindowToNewWorkspace(prev, windowId);
+        newWorkspaceNumber =
+          result.state.workspaces[result.newWorkspaceId].number;
+        return result.state;
+      });
+      return newWorkspaceNumber;
+    },
+    [setState],
+  );
+
   const updateLayout = useCallback(
     (layout: any) => {
       setState((prev) => Logic.updateLayout(prev, layout));
@@ -385,6 +399,7 @@ export const useGrimoire = () => {
     updateWindow,
     removeWindow,
     moveWindowToWorkspace,
+    moveWindowToNewWorkspace,
     updateLayout,
     setActiveWorkspace,
     setActiveAccount,