feat(KB-643): add dashboard scripts management and execution

- Add project settings support and dashboard API helpers for custom scripts
- Add scripts CRUD and run routes backed by terminal sessions with validation and duplicate checks
- Add Scripts modal and header integration for managing and launching project scripts
- Add regression coverage for scripts routes and API client helpers

packages/dashboard/app/components/ScriptsModal.tsx

@@ -4,7 +4,6 @@ import {
   fetchScripts,
   addScript,
   removeScript,
-  type ScriptRunResult,
 } from "../api";
 import type { ToastType } from "../hooks/useToast";