project: Be explicit about project-searchability for buffers (#37773)

Closes https://github.com/zed-industries/zed/issues/28830

Release Notes:

- Fixed builtin buffers and log views showing up in project search

crates/agent_ui/src/acp/thread_view.rs

@@ -4255,7 +4255,7 @@ impl AcpThreadView {
                 }
 
                 let buffer = project.update(cx, |project, cx| {
-                    project.create_local_buffer(&markdown, Some(markdown_language), cx)
+                    project.create_local_buffer(&markdown, Some(markdown_language), true, cx)
                 });
                 let buffer = cx.new(|cx| {
                     MultiBuffer::singleton(buffer, cx).with_title(thread_summary.clone())

crates/agent_ui/src/active_thread.rs

@@ -3585,7 +3585,7 @@ pub(crate) fn open_active_thread_as_markdown(
             }
 
             let buffer = project.update(cx, |project, cx| {
-                project.create_local_buffer(&markdown, Some(markdown_language), cx)
+                project.create_local_buffer(&markdown, Some(markdown_language), true, cx)
             });
             let buffer =
                 cx.new(|cx| MultiBuffer::singleton(buffer, cx).with_title(thread_summary.clone()));