TASK: Fix ad placement on homepage
FILE: src/pages/index.astro
CHANGE: Moved <YandexRTB /> from before <main> to after </main>
BUILD: PASS (npm run build exited 0)
VERIFICATION:
  - dist/index.html: </main> at byte 43284
  - dist/index.html: yandex_rtb at byte 43335
  - Order correct: True (main content before ad block)