docs: readme add saas screenshot

[e06084]

No description provided.

[gemini-code-assist]

Code Review

This pull request adds visual documentation sections for the SaaS dashboard, playground, and evaluation output to the English, Japanese, and Simplified Chinese README files. Feedback was provided to localize the titles and image alt texts in the Japanese and Simplified Chinese versions to maintain consistency with the rest of the documentation.

[gemini-code-assist]

The summary titles and image alt texts in the Japanese README should be localized to maintain consistency with the rest of the document and improve accessibility for Japanese users.

Suggested change

	<details>
	<summary><strong>SaaS — Dashboard</strong></summary>
	<img src="docs/assets/saas_dashboard.png" alt="Dingo SaaS dashboard" />
	</details>
	<details>
	<summary><strong>SaaS — Playground</strong></summary>
	<img src="docs/assets/saas_playground.png" alt="Dingo SaaS playground" />
	</details>
	<details>
	<summary><strong>SaaS — Evaluation output</strong></summary>
	<img src="docs/assets/saas_output.png" alt="Dingo SaaS evaluation output" />
	</details>
	<details>
	<summary><strong>SaaS — ダッシュボード</strong></summary>
	<img src="docs/assets/saas_dashboard.png" alt="Dingo SaaS ダッシュボード" />
	</details>
	<details>
	<summary><strong>SaaS — プレイグラウンド</strong></summary>
	<img src="docs/assets/saas_playground.png" alt="Dingo SaaS プレイグラウンド" />
	</details>
	<details>
	<summary><strong>SaaS — 評価出力</strong></summary>
	<img src="docs/assets/saas_output.png" alt="Dingo SaaS 評価出力" />
	</details>

[gemini-code-assist]

The summary titles and image alt texts in the Simplified Chinese README should be localized to maintain consistency with the rest of the document and improve accessibility for Chinese users.

Suggested change

	<details>
	<summary><strong>SaaS — Dashboard</strong></summary>
	<img src="docs/assets/saas_dashboard.png" alt="Dingo SaaS dashboard" />
	</details>
	<details>
	<summary><strong>SaaS — Playground</strong></summary>
	<img src="docs/assets/saas_playground.png" alt="Dingo SaaS playground" />
	</details>
	<details>
	<summary><strong>SaaS — Evaluation output</strong></summary>
	<img src="docs/assets/saas_output.png" alt="Dingo SaaS evaluation output" />
	</details>
	<details>
	<summary><strong>SaaS — 仪表盘</strong></summary>
	<img src="docs/assets/saas_dashboard.png" alt="Dingo SaaS 仪表盘" />
	</details>
	<details>
	<summary><strong>SaaS — 演练场</strong></summary>
	<img src="docs/assets/saas_playground.png" alt="Dingo SaaS 演练场" />
	</details>
	<details>
	<summary><strong>SaaS — 评估输出</strong></summary>
	<img src="docs/assets/saas_output.png" alt="Dingo SaaS 评估输出" />
	</details>