Enable parallel tool calls for all model prompts (#38499)

## What changed

- Set `parallel_tool_calls` for regular and remote compaction prompts without consulting model metadata.
- Remove `supports_parallel_tool_calls` from `ModelInfo`, the bundled model catalog, and related fixtures.
- Preserve the existing Responses Lite behavior that disables parallel tool calls at request construction.

GitOrigin-RevId: 49552bdf97e71fa57325abb49f8adc0c88f1401a

codex-rs/tui/src/chatwidget/tests/helpers.rs

@@ -282,7 +282,6 @@ fn test_model_info(slug: &str, priority: i32, supports_fast_mode: bool) -> Model
         "default_verbosity": null,
         "apply_patch_tool_type": null,
         "truncation_policy": {"mode": "bytes", "limit": 10_000},
-        "supports_parallel_tool_calls": false,
         "supports_image_detail_original": false,
         "context_window": 272_000,
         "experimental_supported_tools": [],