agent: Allow customizing temperature by provider/model (#30033)

Adds a new `agent.model_parameters` setting that allows the user to
specify a custom temperature for a provider AND/OR model:

```json5
    "model_parameters": [
      // To set parameters for all requests to OpenAI models:
      {
        "provider": "openai",
        "temperature": 0.5
      },
      // To set parameters for all requests in general:
      {
        "temperature": 0
      },
      // To set parameters for a specific provider and model:
      {
        "provider": "zed.dev",
        "model": "claude-3-7-sonnet-latest",
        "temperature": 1.0
      }
    ],
```

Release Notes:

- agent: Allow customizing temperature by provider/model

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/agent/src/terminal_inline_assistant.rs

@@ -6,6 +6,7 @@ use crate::inline_prompt_editor::{
 use crate::terminal_codegen::{CLEAR_INPUT, CodegenEvent, TerminalCodegen};
 use crate::thread_store::{TextThreadStore, ThreadStore};
 use anyhow::{Context as _, Result};
+use assistant_settings::AssistantSettings;
 use client::telemetry::Telemetry;
 use collections::{HashMap, VecDeque};
 use editor::{MultiBuffer, actions::SelectAll};
@@ -266,6 +267,12 @@ impl TerminalInlineAssistant {
             load_context(contexts, project, &assist.prompt_store, cx)
         })?;
 
+        let ConfiguredModel { model, .. } = LanguageModelRegistry::read_global(cx)
+            .inline_assistant_model()
+            .context("No inline assistant model")?;
+
+        let temperature = AssistantSettings::temperature_for_model(&model, cx);
+
         Ok(cx.background_spawn(async move {
             let mut request_message = LanguageModelRequestMessage {
                 role: Role::User,
@@ -287,7 +294,7 @@ impl TerminalInlineAssistant {
                 messages: vec![request_message],
                 tools: Vec::new(),
                 stop: Vec::new(),
-                temperature: None,
+                temperature,
             }
         }))
     }