docs(readme): update Sisyphus Labs banner to new Dori branding

The banner now reflects sisyphuslabs.ai/en's current 'Meet Dori' identity
(headline 'Meet Dori. He ships to 56k stars.' + tagline 'The first AI agent
maintainer of a 56k-star repo.') instead of the older 'Sisyphus is the agent
that codes like your team.' visual, which no longer matches the live site.

- Regenerate .github/assets/sisyphuslabs.png with the new Dori-themed hero
  (Sisyphus Labs wordmark, Greek-column motif, @dori chat mockup, Merged badge).
- Refresh alt text to describe the new banner.
- Bump cache-bust query (?v=2 -> ?v=3) so existing readers re-fetch the asset.
- Apply consistently across all five language READMEs (en/ko/ja/ru/zh-cn).

README.ja.md

@@ -11,7 +11,7 @@
 
 > [!NOTE]
 >
-> [![Sisyphus Labs - Sisyphus is the agent that codes like your team.](./.github/assets/sisyphuslabs.png?v=2)](https://sisyphuslabs.ai)
+> [![Sisyphus Labs - Meet Dori, the AI agent maintainer of a 56k-star repo.](./.github/assets/sisyphuslabs.png?v=3)](https://sisyphuslabs.ai)
 > > **OmO は上記の Jobdori によってメンテナンスされています。あなた専用の Jobdori、Dori に会いましょう。 <br />[こちら](https://sisyphuslabs.ai) からウェイトリストにご登録ください。**
 
 > [!TIP]

README.ko.md

@@ -10,7 +10,7 @@
 
 > [!NOTE]
 >
-> [![Sisyphus Labs - Sisyphus is the agent that codes like your team.](./.github/assets/sisyphuslabs.png?v=2)](https://sisyphuslabs.ai)
+> [![Sisyphus Labs - Meet Dori, the AI agent maintainer of a 56k-star repo.](./.github/assets/sisyphuslabs.png?v=3)](https://sisyphuslabs.ai)
 > > **OmO는 위의 Jobdori에 의해 메인테이닝되고 있습니다. 당신의 Jobdori, Dori를 만나세요. <br />대기 명단은 [여기](https://sisyphuslabs.ai)에서 받습니다.**
 
 > [!TIP]

README.md

@@ -10,7 +10,7 @@
 
 > [!NOTE]
 >
-> [![Sisyphus Labs - Sisyphus is the agent that codes like your team.](./.github/assets/sisyphuslabs.png?v=2)](https://sisyphuslabs.ai)
+> [![Sisyphus Labs - Meet Dori, the AI agent maintainer of a 56k-star repo.](./.github/assets/sisyphuslabs.png?v=3)](https://sisyphuslabs.ai)
 > > **OmO is maintained by Jobdori, the AI assistant shown above. Meet your own Jobdori — Dori. <br />Join the waitlist [here](https://sisyphuslabs.ai).**
 
 > [!TIP]

README.ru.md

@@ -11,7 +11,7 @@
 
 > [!NOTE]
 >
-> [![Sisyphus Labs - Sisyphus is the agent that codes like your team.](./.github/assets/sisyphuslabs.png?v=2)](https://sisyphuslabs.ai)
+> [![Sisyphus Labs - Meet Dori, the AI agent maintainer of a 56k-star repo.](./.github/assets/sisyphuslabs.png?v=3)](https://sisyphuslabs.ai)
 >
 > > **OmO поддерживается Jobdori — ИИ-ассистентом, показанным выше. Познакомьтесь со своим Jobdori — Dori. <br />Присоединяйтесь к листу ожидания [здесь](https://sisyphuslabs.ai).**
 

README.zh-cn.md

@@ -11,7 +11,7 @@
 
 > [!NOTE]
 >
-> [![Sisyphus Labs - Sisyphus is the agent that codes like your team.](./.github/assets/sisyphuslabs.png?v=2)](https://sisyphuslabs.ai)
+> [![Sisyphus Labs - Meet Dori, the AI agent maintainer of a 56k-star repo.](./.github/assets/sisyphuslabs.png?v=3)](https://sisyphuslabs.ai)
 > > **OmO 由上述的 Jobdori 进行维护。认识你专属的 Jobdori — Dori。<br />[在此处](https://sisyphuslabs.ai)加入等待名单。**
 
 > [!TIP]