chore(features) rm Feature::ApplyPatchFreeform (#22711)

## Summary
Removes the feature since this is effectively on by default in all cases
where we should use it, or can be configured via models.json.

## Testing
- [x] unit tests pass

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

@@ -4320,7 +4320,6 @@ async fn feature_table_overrides_legacy_flags() -> std::io::Result<()> {
     .await?;
 
     assert!(!config.features.enabled(Feature::ApplyPatchFreeform));
-    assert!(!config.include_apply_patch_tool);
 
     Ok(())
 }
@@ -7505,7 +7504,6 @@ async fn test_precedence_fixture_with_o3_profile() -> std::io::Result<()> {
             compact_prompt: None,
             forced_chatgpt_workspace_id: None,
             forced_login_method: None,
-            include_apply_patch_tool: true,
             web_search_mode: Constrained::allow_any(WebSearchMode::Cached),
             web_search_config: None,
             use_experimental_unified_exec_tool: !cfg!(windows),
@@ -7954,7 +7952,6 @@ async fn test_precedence_fixture_with_gpt3_profile() -> std::io::Result<()> {
         compact_prompt: None,
         forced_chatgpt_workspace_id: None,
         forced_login_method: None,
-        include_apply_patch_tool: true,
         web_search_mode: Constrained::allow_any(WebSearchMode::Cached),
         web_search_config: None,
         use_experimental_unified_exec_tool: !cfg!(windows),
@@ -8117,7 +8114,6 @@ async fn test_precedence_fixture_with_zdr_profile() -> std::io::Result<()> {
         compact_prompt: None,
         forced_chatgpt_workspace_id: None,
         forced_login_method: None,
-        include_apply_patch_tool: true,
         web_search_mode: Constrained::allow_any(WebSearchMode::Cached),
         web_search_config: None,
         use_experimental_unified_exec_tool: !cfg!(windows),
@@ -8265,7 +8261,6 @@ async fn test_precedence_fixture_with_gpt5_profile() -> std::io::Result<()> {
         compact_prompt: None,
         forced_chatgpt_workspace_id: None,
         forced_login_method: None,
-        include_apply_patch_tool: true,
         web_search_mode: Constrained::allow_any(WebSearchMode::Cached),
         web_search_config: None,
         use_experimental_unified_exec_tool: !cfg!(windows),

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

@@ -348,12 +348,10 @@ pub(crate) fn validate_feature_requirements_in_config_toml(
         let configured_features = Features::from_sources(
             FeatureConfigSource {
                 features: cfg.features.as_ref(),
-                include_apply_patch_tool: None,
                 experimental_use_unified_exec_tool: cfg.experimental_use_unified_exec_tool,
             },
             FeatureConfigSource {
                 features: profile.features.as_ref(),
-                include_apply_patch_tool: None,
                 experimental_use_unified_exec_tool: profile.experimental_use_unified_exec_tool,
             },
             FeatureOverrides::default(),

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

@@ -764,11 +764,6 @@ pub struct Config {
     /// When set, restricts the login mechanism users may use.
     pub forced_login_method: Option<ForcedLoginMethod>,
 
-    /// Include the `apply_patch` tool for models that benefit from invoking
-    /// file edits as a structured tool call. When unset, this falls back to the
-    /// model info's default preference.
-    pub include_apply_patch_tool: bool,
-
     /// Explicit or feature-derived web search mode.
     pub web_search_mode: Constrained<WebSearchMode>,
 
@@ -2301,12 +2296,10 @@ impl Config {
         let configured_features = Features::from_sources(
             FeatureConfigSource {
                 features: cfg.features.as_ref(),
-                include_apply_patch_tool: None,
                 experimental_use_unified_exec_tool: cfg.experimental_use_unified_exec_tool,
             },
             FeatureConfigSource {
                 features: config_profile.features.as_ref(),
-                include_apply_patch_tool: None,
                 experimental_use_unified_exec_tool: config_profile
                     .experimental_use_unified_exec_tool,
             },
@@ -2845,7 +2838,6 @@ impl Config {
             config
         };
 
-        let include_apply_patch_tool_flag = features.enabled(Feature::ApplyPatchFreeform);
         let use_experimental_unified_exec_tool = features.enabled(Feature::UnifiedExec);
 
         let forced_chatgpt_workspace_id = cfg
@@ -3257,7 +3249,6 @@ impl Config {
             experimental_thread_store: thread_store_config(cfg.experimental_thread_store),
             forced_chatgpt_workspace_id,
             forced_login_method,
-            include_apply_patch_tool: include_apply_patch_tool_flag,
             web_search_mode: constrained_web_search_mode.value,
             web_search_config,
             use_experimental_unified_exec_tool,