* 📝 docs: Remove Langfuse docs; enable pg_search
Delete Langfuse observability guides (langfuse.mdx and langfuse.zh-CN.mdx). Update Docker self-hosting docs to add `-c shared_preload_libraries=pg_search` to the ParadeDB docker run command and clarify that the ParadeDB image includes pgvector and pg_search and that pg_search must be explicitly enabled; apply the same clarification to the Chinese documentation.
* 📝 docs: Document 'video' capability in model list
Add a `video` entry to the extension capabilities table in docs/self-hosting/advanced/model-list.mdx and its Chinese translation (model-list.zh-CN.mdx) to document Video Comprehension support.
* 📝 docs: Add agent feature flags & update thread text
Add documentation entries for new system agent feature flags: generationTopic (AI image automatic topic naming), inputCompletion (input auto-completion suggestions), and promptRewrite (prompt optimization before generation). Also reword the thread/branch conversation entry to clarify automatic title generation. Apply the same updates to the Chinese localization file.
* 📝 docs: Document AGENT_GATEWAY_SERVICE_TOKEN env var
Add documentation for the AGENT_GATEWAY_SERVICE_TOKEN environment variable to the self-hosting environment variables pages (English and Chinese). The new entries specify that the variable is optional, describe it as the authentication token used between Gateway Mode and a self-deployed Agent Gateway, and include default (-) and example (`dev-secret`). Files changed: docs/self-hosting/environment-variables/basic.mdx and basic.zh-CN.mdx.
Sui_Feng