feat(KB-503): add multi-project CLI support with project subcommands

- Add project subcommands: list, add, remove, show, set-default, detect
- Add --project flag support for all task commands
- Create project-context.ts utilities for project resolution
- Add defaultProjectId to GlobalSettings type
- Implement project auto-detection from cwd
- Update CLI argument parsing for global --project flag
- Add multi-project CLI documentation to AGENTS.md

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

@@ -128,7 +128,7 @@ describe("NewTaskModal", () => {
     fireEvent.click(screen.getByRole("button", { name: "Create Task" }));
     
     await waitFor(() => {
-      expect(props.addToast).toHaveBeenCalledWith("Created KB-042", "success");
+      expect(props.addToast).toHaveBeenCalledWith("Created FN-042", "success");
     });
   });