Rename assistant_settings to agent_settings (#31513)

This PR renames the `assistant_settings` crate to `agent_settings`, as
well a number of constructs within it.

Release Notes:

- N/A

crates/assistant_context_editor/src/context.rs

@@ -1,8 +1,8 @@
 #[cfg(test)]
 mod context_tests;
 
+use agent_settings::AgentSettings;
 use anyhow::{Context as _, Result, bail};
-use assistant_settings::AssistantSettings;
 use assistant_slash_command::{
     SlashCommandContent, SlashCommandEvent, SlashCommandLine, SlashCommandOutputSection,
     SlashCommandResult, SlashCommandWorkingSet,
@@ -2266,8 +2266,7 @@ impl AssistantContext {
             tools: Vec::new(),
             tool_choice: None,
             stop: Vec::new(),
-            temperature: model
-                .and_then(|model| AssistantSettings::temperature_for_model(model, cx)),
+            temperature: model.and_then(|model| AgentSettings::temperature_for_model(model, cx)),
         };
         for message in self.messages(cx) {
             if message.status != MessageStatus::Done {