Symptom

Users reported "退出再进来 design 都没了" — generated designs were correctly persisted to SQLite (design_snapshots rows confirmed present), but on relaunch the hub appeared empty.

Root cause

apps/desktop/src/renderer/src/App.tsx only invoked loadConfig() in the startup useEffect. The store already had loadDesigns() (which calls window.codesign.snapshots.listDesigns() and populates designs), but nothing in the renderer ever called it on mount. So the in-memory list stayed empty even though the DB had rows.

Fix

• App startup effect now runs loadConfig and loadDesigns in parallel.
• After they resolve, if currentDesignId is null and at least one persisted design exists, auto-switchDesign to the most recent one (first item — listDesigns is already sorted by activity), so users land back on their last work.
• Added a Vitest case in store.test.ts that stubs listDesigns to return 2 rows and verifies state.designs.length === 2 plus designsLoaded === true.

This completes the persistence flow opened by #93.

Four checks

• Compatibility: green — no IPC / schema changes, only renderer wiring.
• Upgradeability: green — uses existing loadDesigns / switchDesign actions.
• No bloat: green — no new deps, ~10 lines added in App.tsx.
• Elegance: green — reuses existing store actions; explicit, no factories.

Test plan

• pnpm test — 293 passed (was 292; +1 new case).
• pnpm lint — passes (existing warnings only).
• Manual: start app → create design → quit → relaunch → confirm design appears in hub and last design is restored.