refactor(frontend): migrate Svelte stores from .ts to .svelte.ts runes
- Delete legacy .ts stores (auth, activity, assistantChat, datasetReview, environmentContext, health, sidebar, taskDrawer, translationRun)
- Create new .svelte.ts runes-based stores using reactive primitives
- Migrate i18n: /i18n → /i18n/index.svelte.js
- Migrate toasts: /toasts → /toasts.svelte.js
- Update all component imports across 180+ files: components, pages, routes, lib
- Remove fromStore() wrappers — use store.value directly with Svelte 5 runes
- Update test mocks for new import paths
- Add @DEPRECATED annotation to legacy alias
busya
4fc3356312