Improve eSpace Foundry docs: make `-g` parameter requirement more prominent

[darwintree]

Describe the feature or improvement 描述新特性或改进

When using Foundry on Conflux eSpace, users need to add the -g parameter, and 250 is the recommended value. The current documentation already mentions this, but the note is not prominent enough and can be easily missed.

Suggested improvement:

• Highlight the requirement near the first Foundry command/example instead of only mentioning it in less prominent text.
• Explicitly state the recommended value: -g 250.
• Clarify that omitting this parameter may cause confusion or execution issues for users following the guide directly.

Optional: Affected page(s) or section(s) 受影响的页面

Foundry-related documentation under eSpace.

Optional: Why is this feature or improvement important? 为什么需要这个新特性或改进？

This is a practical prerequisite for successfully using Foundry on eSpace. If it is easy to miss, users may encounter avoidable errors or unexpected behavior, which directly hurts the onboarding experience.

Optional: Implementation ideas 如何实现

• Add a tip/warning block near the beginning of the relevant Foundry page(s).
• Update code examples to include -g 250 where appropriate.
• Ensure the wording is visible enough in both overview and step-by-step sections.

Optional: Additional context 其他上下文信息

User suggestion: the documentation already has this information, but it is not visually prominent enough.