Retire worktree and voice feature flags (#54175)

## What changed

- Remove feature-flag checks from managed worktree creation and repository-aware session discovery, while retaining local workspace and trust checks.
- Make TUI voice availability follow platform support instead of `features.realtime_conversation`.
- Ignore `features.worktrees` and `features.realtime_conversation` configuration overrides, warn when managed requirements reference them, and hide both flags from `/experimental`, including catalogs from older servers.

## Testing

Add coverage for ignored configuration overrides and managed requirements, and update session filtering, worktree grouping, and experimental feature discovery tests for the retired flags.

GitOrigin-RevId: 1d64e890e6e2f8a78926a9ea163126c0890b068e

codex-rs/core/src/config/config_tests.rs

@@ -11909,6 +11909,8 @@ shell_tool = false
 
 #[test_case::test_case(Feature::Personality; "personality")]
 #[test_case::test_case(Feature::GuardianThreadContext; "guardian thread context")]
+#[test_case::test_case(Feature::Worktrees; "worktrees")]
+#[test_case::test_case(Feature::RealtimeConversation; "realtime conversation")]
 #[test_case::test_case(Feature::ShellZshFork; "shell zsh fork")]
 #[test_case::test_case(Feature::UnifiedExecZshFork; "unified exec zsh fork")]
 fn retired_feature_requirements_do_not_pin_configured_values(
@@ -11960,6 +11962,13 @@ fn retired_feature_requirements_do_not_pin_configured_values(
                 usize::from(feature != Feature::Personality),
             ),
         );
+        if matches!(feature, Feature::Worktrees | Feature::RealtimeConversation) {
+            assert!(
+                warnings[0].contains(&format!("Ignoring removed `features` requirement `{key}`"))
+            );
+            assert!(warnings[0].contains("enterprise"));
+            assert!(warnings[0].contains("availability no longer depends on this feature flag"));
+        }
     }
 
     Ok(())

codex-rs/core/src/config/managed_features.rs

@@ -243,6 +243,15 @@ fn parse_feature_requirements(
         if key == Feature::Personality.key() {
             continue;
         }
+        if key == Feature::Worktrees.key() || key == Feature::RealtimeConversation.key() {
+            push_feature_requirement_warning(
+                &mut startup_warnings,
+                format!(
+                    "Ignoring removed `features` requirement `{key}` from {source}; availability no longer depends on this feature flag."
+                ),
+            );
+            continue;
+        }
         if matches!(key.as_str(), "shell_zsh_fork" | "unified_exec_zsh_fork") {
             push_feature_requirement_warning(
                 &mut startup_warnings,