home polish: continue-watching hero, progress bars, posters, time-ago

- showHome(): most recent entry renders as a hero card (poster,
  episode/lang/position, progress bar, Resume); the rest become
  mini poster cards with progress + relative timestamp
- history entries now persist dur (video.duration) and poster;
  /api/anime returns poster (parsed from the details page)
- old entries without dur render without a bar (backward compatible)
- browser test asserts the seeded entry, not a section header that
  only existed via a cross-test side effect

tests/test_browser.py

@@ -50,7 +50,7 @@ async def test_login_ui():
         await page.click("#go")
         await _login_settled(page)
         assert await page.inner_text("#me") == "hi, admin"
-        assert "Recently played" in await page.inner_text("#main"), "seeded history must show"
+        assert "Seed Anime" in await page.inner_text("#main"), "seeded history must show"
         assert not errors, errors
         await browser.close()
     print("ok test_login_ui")