feat: add methods catalog, detail pages, BMI calculator

- Create 16 diet/weight methods across 5 categories with full content
- Add MethodsPage with search, filters (category/difficulty/effectiveness)
- Add MethodDetailPage with pros/cons, scientific basis, contraindications
- Add BmiCalculatorPage with visual BMI scale
- Create reusable components: Badge, DifficultyBadge, EffectivenessIndicator,
  BookmarkButton, MethodCard, SearchBar, FilterPanel
- Add useLocalStorage and useBookmarks hooks for localStorage persistence
- Set up React Router with all routes

Co-authored-by: Cursor <cursoragent@cursor.com>

tsconfig.app.tsbuildinfo

@@ -1 +1 @@
-{"root":["./src/app.tsx","./src/main.tsx","./src/vite-env.d.ts","./src/components/footer.tsx","./src/components/header.tsx","./src/components/layout.tsx","./src/pages/homepage.tsx"],"version":"5.9.3"}
+{"root":["./src/app.tsx","./src/main.tsx","./src/vite-env.d.ts","./src/components/badge.tsx","./src/components/bookmarkbutton.tsx","./src/components/difficultybadge.tsx","./src/components/effectivenessindicator.tsx","./src/components/filterpanel.tsx","./src/components/footer.tsx","./src/components/header.tsx","./src/components/layout.tsx","./src/components/methodcard.tsx","./src/components/searchbar.tsx","./src/data/methods.ts","./src/hooks/usebookmarks.ts","./src/hooks/uselocalstorage.ts","./src/pages/bmicalculatorpage.tsx","./src/pages/homepage.tsx","./src/pages/methoddetailpage.tsx","./src/pages/methodspage.tsx","./src/types/method.ts","./src/utils/bmi.ts"],"version":"5.9.3"}