Agent thread performance degrades significantly with large content, needs lazy loading implementation

Reproduction steps

1. Open Zed editor with a project containing large files (several MBs) or content-intensive workspace
2. Activate features that utilize the agent thread
3. Observe significant performance degradation, lag, or unresponsiveness in the UI when working with large content
4. Monitor the agent thread during these operations and notice it becoming sluggish when processing large volume of data

Current vs. Expected behavior

Current behavior: The agent thread in Zed becomes significantly slow when processing large amounts of content, leading to UI freezes, delays in language server features, AI assistant responses, and overall degraded performance that makes the editor unresponsive during intensive operations.

Expected behavior: The agent should handle large content efficiently through lazy loading mechanisms, chunked processing, or other performance optimizations to maintain responsiveness and avoid significant slowdowns when working with large files or extensive content.

Zed version and system specs

Main branch

Attach Zed log file

No response

Relevant Zed settings

No response

(for AI issues) Model provider details

No response

If you are using WSL on Windows, what flavor of Linux are you using?

None