chore(i18n): update Simplified Chinese localization

[zhen-shi]

1. Proofread and optimize existing Simplified Chinese translation:

   • Align fediverse proper nouns with Mastodon Community Translation, including following, follower, status, pin, favourite, boost, and so on.

   • Optimize descriptions, fix grammatical errors.

   • Enhance error messages to be more user-friendly.

2. Add Simplified Chinese translation of Streaming and AI feature.

[Jerry23011]

LGTM

What do you think CC @nixzhu

[nixzhu]

LGTM