Add assistant_context_editor crate (#23429)

This PR adds a new `assistant_context_editor` crate.

This will ultimately house the `ContextEditor` so that it can be
consumed by both `assistant` and `assistant2`.

For the purposes of this PR, we just introduce the crate and move some
supporting constructs to it, such as the `ContextStore`.

Release Notes:

- N/A

crates/collab/Cargo.toml

@@ -79,6 +79,7 @@ uuid.workspace = true
 
 [dev-dependencies]
 assistant = { workspace = true, features = ["test-support"] }
+assistant_context_editor.workspace = true
 assistant_slash_command.workspace = true
 assistant_tool.workspace = true
 async-trait.workspace = true

crates/collab/src/tests/integration_tests.rs

@@ -6,7 +6,7 @@ use crate::{
     },
 };
 use anyhow::{anyhow, Result};
-use assistant::ContextStore;
+use assistant_context_editor::ContextStore;
 use assistant_slash_command::SlashCommandWorkingSet;
 use assistant_tool::ToolWorkingSet;
 use call::{room, ActiveCall, ParticipantLocation, Room};

crates/collab/src/tests/test_server.rs

@@ -308,7 +308,7 @@ impl TestServer {
                 settings::KeymapFile::load_asset_allow_partial_failure(os_keymap, cx).unwrap(),
             );
             language_model::LanguageModelRegistry::test(cx);
-            assistant::context_store::init(&client.clone().into());
+            assistant_context_editor::init(client.clone(), cx);
         });
 
         client