Always send reasoning parameters in Responses requests (#32206)

## What changed

- Build a reasoning payload for every Responses request and always include `reasoning.encrypted_content`.
- Remove `supports_reasoning_summaries` from model metadata and retire the `model_supports_reasoning_summaries` configuration override.
- Use configured or model-default reasoning effort without a capability gate, including for guardian reviews and tracing.

GitOrigin-RevId: 2c9f194a5d2d4d688a2235299e6358f82ab8e1ea

codex-rs/codex-api/src/endpoint/models.rs

@@ -209,7 +209,6 @@ mod tests {
                     "priority": 1,
                     "upgrade": null,
                     "base_instructions": "base instructions",
-                    "supports_reasoning_summaries": false,
                     "support_verbosity": false,
                     "default_verbosity": null,
                     "apply_patch_tool_type": null,

codex-rs/codex-api/tests/models_integration.rs

@@ -81,7 +81,6 @@ async fn models_client_hits_models_endpoint() {
             base_instructions: "base instructions".to_string(),
             model_messages: None,
             include_skills_usage_instructions: false,
-            supports_reasoning_summaries: false,
             default_reasoning_summary: ReasoningSummary::Auto,
             support_verbosity: false,
             default_verbosity: None,