Remove moved third-party tools from agent CHANGELOG

Remove tools that have been moved to the toolbox package from the agent
CHANGELOG to avoid duplication and maintain accurate documentation:

Removed tools:
- Brave for web search integration
- Mapbox for geocoding addresses to coordinates and reverse geocoding
- OpenMeteo for weather information
- SerpApi for search engine results
- Tavily for AI-powered search
- Wikipedia for Wikipedia content retrieval
- YouTubeTranscriber for YouTube video transcription

Kept agent-specific tools:
- SimilaritySearch for RAG/vector store searches
- Agent allowing agents to use other agents as tools
- Clock for current date/time
- Crawler for web page crawling

Author: OskarStark

src/agent/CHANGELOG.md

@@ -24,14 +24,7 @@ CHANGELOG
    - `SimilaritySearch` for RAG/vector store searches
    - `Agent` allowing agents to use other agents as tools
    - `Clock` for current date/time
-   - `Brave` for web search integration
    - `Crawler` for web page crawling
-   - `Mapbox` for geocoding addresses to coordinates and reverse geocoding
-   - `OpenMeteo` for weather information
-   - `SerpApi` for search engine results
-   - `Tavily` for AI-powered search
-   - `Wikipedia` for Wikipedia content retrieval
-   - `YouTubeTranscriber` for YouTube video transcription
  * Add structured output support:
    - PHP class output with automatic conversion from LLM responses
    - Array structure output with JSON schema validation