fix: add more fields to ThreadStartResponse and ThreadResumeResponse (#6847)

This adds the following fields to `ThreadStartResponse` and
`ThreadResumeResponse`:

```rust
    pub model: String,
    pub model_provider: String,
    pub cwd: PathBuf,
    pub approval_policy: AskForApproval,
    pub sandbox: SandboxPolicy,
    pub reasoning_effort: Option<ReasoningEffort>,
```

This is important because these fields are optional in
`ThreadStartParams` and `ThreadResumeParams`, so the caller needs to be
able to determine what values were ultimately used to start/resume the
conversation. (Though note that any of these could be changed later
between turns in the conversation.)

Though to get this information reliably, it must be read from the
internal `SessionConfiguredEvent` that is created in response to the
start of a conversation. Because `SessionConfiguredEvent` (as defined in
`codex-rs/protocol/src/protocol.rs`) did not have all of these fields, a
number of them had to be added as part of this PR.

Because `SessionConfiguredEvent` is referenced in many tests, test
instances of `SessionConfiguredEvent` had to be updated, as well, which
is why this PR touches so many files.

codex-rs/protocol/src/protocol.rs

@@ -1469,7 +1469,7 @@ pub struct ListCustomPromptsResponseEvent {
     pub custom_prompts: Vec<CustomPrompt>,
 }
 
-#[derive(Debug, Default, Clone, Deserialize, Serialize, JsonSchema, TS)]
+#[derive(Debug, Clone, Deserialize, Serialize, JsonSchema, TS)]
 pub struct SessionConfiguredEvent {
     /// Name left as session_id instead of conversation_id for backwards compatibility.
     pub session_id: ConversationId,
@@ -1477,6 +1477,18 @@ pub struct SessionConfiguredEvent {
     /// Tell the client what model is being queried.
     pub model: String,
 
+    pub model_provider_id: String,
+
+    /// When to escalate for approval for execution
+    pub approval_policy: AskForApproval,
+
+    /// How to sandbox commands executed in the system
+    pub sandbox_policy: SandboxPolicy,
+
+    /// Working directory that should be treated as the *root* of the
+    /// session.
+    pub cwd: PathBuf,
+
     /// The effort the model is putting into reasoning about the user's request.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub reasoning_effort: Option<ReasoningEffortConfig>,
@@ -1562,6 +1574,7 @@ mod tests {
     use crate::items::UserMessageItem;
     use crate::items::WebSearchItem;
     use anyhow::Result;
+    use pretty_assertions::assert_eq;
     use serde_json::json;
     use tempfile::NamedTempFile;
 
@@ -1606,6 +1619,10 @@ mod tests {
             msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
                 session_id: conversation_id,
                 model: "codex-mini-latest".to_string(),
+                model_provider_id: "openai".to_string(),
+                approval_policy: AskForApproval::Never,
+                sandbox_policy: SandboxPolicy::ReadOnly,
+                cwd: PathBuf::from("/home/user/project"),
                 reasoning_effort: Some(ReasoningEffortConfig::default()),
                 history_log_id: 0,
                 history_entry_count: 0,
@@ -1620,6 +1637,12 @@ mod tests {
                 "type": "session_configured",
                 "session_id": "67e55044-10b1-426f-9247-bb680e5fe0c8",
                 "model": "codex-mini-latest",
+                "model_provider_id": "openai",
+                "approval_policy": "never",
+                "sandbox_policy": {
+                    "type": "read-only"
+                },
+                "cwd": "/home/user/project",
                 "reasoning_effort": "medium",
                 "history_log_id": 0,
                 "history_entry_count": 0,