feat(KB-332): rename task prefix from KB to FN and branches from kb/ to fusion/

- Change default task prefix from KB to FN across all packages

- Rename branch naming pattern from kb/{id} to fusion/{id}

- Update all test assertions and fixtures to use new prefixes

- Add changeset for the breaking change

- Resolve merge conflicts in TaskCard.test.tsx touch gesture tests

packages/dashboard/app/components/TaskCard.test.tsx

@@ -26,7 +26,7 @@ import { uploadAttachment } from "../api";
 
 function makeTask(overrides: Partial<Task> = {}): Task {
   return {
-    id: "KB-001",
+    id: "FN-001",
     title: "Test task",
     column: "in-progress",
     status: undefined as any,
@@ -42,7 +42,7 @@ const noop = () => {};
 describe("TaskCard", () => {
   it("renders the card ID text", () => {
     render(<TaskCard task={makeTask()} onOpenDetail={noop} addToast={noop} />);
-    expect(screen.getByText("KB-001")).toBeDefined();
+    expect(screen.getByText("FN-001")).toBeDefined();
   });
 
   it("renders the status badge when task.status is set", () => {
@@ -133,7 +133,7 @@ describe("TaskCard", () => {
     });
 
     await waitFor(() => {
-      expect(mockUpload).toHaveBeenCalledWith("KB-001", file);
+      expect(mockUpload).toHaveBeenCalledWith("FN-001", file);
       expect(addToast).toHaveBeenCalledWith(
         expect.stringContaining("Attached test.png"),
         "success",