chore: delete unused files flagged by knip

38 files removed across app and server (verified unreferenced via
grep + typecheck). Includes dead components, hooks, stores, utils,
POC scripts, an empty orchestrator stub, stale playwright configs,
and a duplicate workspace-registry test-helpers module.

knip config tightened: added babel.config.js, native platform
extensions, and test-stubs/ to app entry patterns.

packages/app/src/stores/section-order-store.ts

@@ -1,79 +0,0 @@
-import { create } from "zustand";
-import { persist, createJSONStorage } from "zustand/middleware";
-import AsyncStorage from "@react-native-async-storage/async-storage";
-
-interface SectionOrderState {
-  /** Ordered array of project keys. Projects not in this list appear at the end in their natural order. */
-  projectOrder: string[];
-
-  /** Set the full order of project keys */
-  setProjectOrder: (order: string[]) => void;
-
-  /** Move a project to a new index */
-  moveProject: (fromIndex: number, toIndex: number) => void;
-}
-
-export const useSectionOrderStore = create<SectionOrderState>()(
-  persist(
-    (set) => ({
-      projectOrder: [],
-
-      setProjectOrder: (order) => set({ projectOrder: order }),
-
-      moveProject: (fromIndex, toIndex) =>
-        set((state) => {
-          const newOrder = [...state.projectOrder];
-          const [removed] = newOrder.splice(fromIndex, 1);
-          if (removed !== undefined) {
-            newOrder.splice(toIndex, 0, removed);
-          }
-          return { projectOrder: newOrder };
-        }),
-    }),
-    {
-      name: "section-order",
-      storage: createJSONStorage(() => AsyncStorage),
-      partialize: (state) => ({
-        projectOrder: state.projectOrder,
-      }),
-    },
-  ),
-);
-
-/**
- * Sort project groups according to persisted order.
- * Projects not in the persisted order appear at the end in their original order.
- */
-export function sortProjectsByStoredOrder<T extends { projectKey: string }>(
-  groups: T[],
-  storedOrder: string[],
-): T[] {
-  if (storedOrder.length === 0) {
-    return groups;
-  }
-
-  const orderMap = new Map(storedOrder.map((key, index) => [key, index]));
-
-  return [...groups].sort((a, b) => {
-    const aIndex = orderMap.get(a.projectKey);
-    const bIndex = orderMap.get(b.projectKey);
-
-    // Both have stored order - sort by stored order
-    if (aIndex !== undefined && bIndex !== undefined) {
-      return aIndex - bIndex;
-    }
-
-    // Only a has stored order - a comes first
-    if (aIndex !== undefined) {
-      return -1;
-    }
-
-    // Only b has stored order - b comes first
-    if (bIndex !== undefined) {
-      return 1;
-    }
-
-    // Neither has stored order - maintain original order (stable sort)
-    return 0;
-  });
-}