refactor(FN-1289): extract AppInner logic into hooks and modal component

- Extract view state, project actions, and task handler concerns from AppInner into dedicated hooks
- Add AppModals component to centralize modal rendering and related props wiring
- Inline thin aliases and complete AppInner cleanup after moving responsibilities out
- Add unit tests for useViewState, useProjectActions, and useTaskHandlers hooks

packages/dashboard/app/hooks/useTaskHandlers.ts

@@ -0,0 +1,70 @@
+import { useCallback } from "react";
+import type { Task, TaskCreateInput } from "@fusion/core";
+import type { ToastType } from "./useToast";
+
+interface UseTaskHandlersOptions {
+  createTask: (input: TaskCreateInput) => Promise<Task>;
+  onPlanningTaskCreated: (task: Task, addToast: (msg: string, type?: ToastType) => void) => void;
+  onPlanningTasksCreated: (tasks: Task[], addToast: (msg: string, type?: ToastType) => void) => void;
+  onSubtaskTasksCreated: (tasks: Task[], addToast: (msg: string, type?: ToastType) => void) => void;
+  addToast: (message: string, type?: ToastType) => void;
+}
+
+export interface UseTaskHandlersResult {
+  handleBoardQuickCreate: (input: TaskCreateInput) => Promise<void>;
+  handleModalCreate: (input: TaskCreateInput) => Promise<Task>;
+  handlePlanningTaskCreated: (task: Task) => void;
+  handlePlanningTasksCreated: (tasks: Task[]) => void;
+  handleSubtaskTasksCreated: (tasks: Task[]) => void;
+  handleGitHubImport: (task: Task) => void;
+}
+
+export function useTaskHandlers(options: UseTaskHandlersOptions): UseTaskHandlersResult {
+  const {
+    createTask,
+    onPlanningTaskCreated,
+    onPlanningTasksCreated,
+    onSubtaskTasksCreated,
+    addToast,
+  } = options;
+
+  const handleBoardQuickCreate = useCallback(
+    async (input: TaskCreateInput): Promise<void> => {
+      await createTask({ ...input, column: "triage" });
+    },
+    [createTask],
+  );
+
+  const handleModalCreate = useCallback(
+    async (input: TaskCreateInput): Promise<Task> => {
+      const task = await createTask({ ...input, column: "triage" });
+      return task;
+    },
+    [createTask],
+  );
+
+  const handlePlanningTaskCreated = useCallback((task: Task) => {
+    onPlanningTaskCreated(task, addToast);
+  }, [onPlanningTaskCreated, addToast]);
+
+  const handlePlanningTasksCreated = useCallback((tasks: Task[]) => {
+    onPlanningTasksCreated(tasks, addToast);
+  }, [onPlanningTasksCreated, addToast]);
+
+  const handleSubtaskTasksCreated = useCallback((tasks: Task[]) => {
+    onSubtaskTasksCreated(tasks, addToast);
+  }, [onSubtaskTasksCreated, addToast]);
+
+  const handleGitHubImport = useCallback((task: Task) => {
+    addToast(`Imported ${task.id} from GitHub`, "success");
+  }, [addToast]);
+
+  return {
+    handleBoardQuickCreate,
+    handleModalCreate,
+    handlePlanningTaskCreated,
+    handlePlanningTasksCreated,
+    handleSubtaskTasksCreated,
+    handleGitHubImport,
+  };
+}