Always put Code Mode tool descriptions before namespace descriptions (#57462)

## What changed

Make tool descriptions precede namespace descriptions in Code Mode execution and tool search. Mark `code_mode_tool_description_first` as removed and simplify cached definitions to depend only on the input schema budget.

## Testing

Update Code Mode integration assertions and catalog snapshots to expect tool descriptions before namespace descriptions.

GitOrigin-RevId: 1344d4c264d1d2b18ee0388a064b6813ca81f770

codex-rs/features/src/lib.rs

@@ -152,7 +152,7 @@ pub enum Feature {
     CodeModePrewarm,
     /// Terminate active code mode cells when their turn is interrupted.
     CodeModeInterrupt,
-    /// Put each tool's description before its namespace description in Code Mode.
+    /// Removed compatibility flag for Code Mode tool description ordering.
     CodeModeToolDescriptionFirst,
     /// Restrict model-visible tools to code mode entrypoints (`exec`, `wait`).
     CodeModeOnly,
@@ -1280,7 +1280,7 @@ pub const FEATURES: &[FeatureSpec] = &[
     FeatureSpec {
         id: Feature::CodeModeToolDescriptionFirst,
         key: "code_mode_tool_description_first",
-        stage: Stage::UnderDevelopment,
+        stage: Stage::Removed,
         default_enabled: false,
     },
     FeatureSpec {