feat: make reasoning effort/summaries configurable (#1199)

Previous to this PR, we always set `reasoning` when making a request
using the Responses API:


d7245cbbc9/codex-rs/core/src/client.rs (L108-L111)

Though if you tried to use the Rust CLI with `--model gpt-4.1`, this
would fail with:

```shell
"Unsupported parameter: 'reasoning.effort' is not supported with this model."
```

We take a cue from the TypeScript CLI, which does a check on the model
name:


d7245cbbc9/codex-cli/src/utils/agent/agent-loop.ts (L786-L789)

This PR does a similar check, though also adds support for the following
config options:

```
model_reasoning_effort = "low" | "medium" | "high" | "none"
model_reasoning_summary = "auto" | "concise" | "detailed" | "none"
```

This way, if you have a model whose name happens to start with `"o"` (or
`"codex"`?), you can set these to `"none"` to explicitly disable
reasoning, if necessary. (That said, it seems unlikely anyone would use
the Responses API with non-OpenAI models, but we provide an escape
hatch, anyway.)

This PR also updates both the TUI and `codex exec` to show `reasoning
effort` and `reasoning summaries` in the header.

codex-rs/core/src/protocol.rs

@@ -12,6 +12,8 @@ use serde::Deserialize;
 use serde::Serialize;
 use uuid::Uuid;
 
+use crate::config_types::ReasoningEffort as ReasoningEffortConfig;
+use crate::config_types::ReasoningSummary as ReasoningSummaryConfig;
 use crate::message_history::HistoryEntry;
 use crate::model_provider_info::ModelProviderInfo;
 
@@ -37,6 +39,10 @@ pub enum Op {
 
         /// If not specified, server will use its default model.
         model: String,
+
+        model_reasoning_effort: ReasoningEffortConfig,
+        model_reasoning_summary: ReasoningSummaryConfig,
+
         /// Model instructions
         instructions: Option<String>,
         /// When to escalate for approval for execution