Add an option to omit descriptions from skill catalogs (#57500)

## What changed

Add the disabled-by-default `omit_skill_descriptions` feature flag to omit descriptions from model-visible host, executor, and cloud skill catalogs while retaining names and locators. Adapt catalog introductions, usage instructions, and alias budget accounting to the selected policy.

Persist the description policy in catalog snapshots and refresh usage instructions when it changes. Ignore description-only edits in catalog deltas while descriptions are omitted.

## Testing

Add coverage for alias token budgets, policy changes with older snapshots, and suppressed description-only updates. Extend scenario snapshots to cover plugin visibility and catalog deduplication with descriptions omitted.

GitOrigin-RevId: 5bf1dcee8c04059c7a78998affc1efcdef8ec883

codex-rs/cli/src/main.rs

@@ -2170,6 +2170,9 @@ async fn run_debug_prompt_input_command(
             catalog_deltas_enabled: config
                 .features
                 .enabled(codex_features::Feature::SkillCatalogDeltas),
+            omit_descriptions: config
+                .features
+                .enabled(codex_features::Feature::OmitSkillDescriptions),
             max_context_tokens: config.skill_max_context_tokens,
             bundled_skills_enabled: config.bundled_skills_enabled(),
             cloud_skill_enabled: config.cloud_skill_enabled,