app-server: include experimental skill metadata in exec approval requests (#13929)

## Summary

This change surfaces skill metadata on command approval requests so
app-server clients can tell when an approval came from a skill script
and identify the originating `SKILL.md`.

- add `skill_metadata` to exec approval events in the shared protocol
- thread skill metadata through core shell escalation and delegated
approval handling for skill-triggered approvals
- expose the field in app-server v2 as experimental `skillMetadata`
- regenerate the JSON/TypeScript schemas and cover the new field in
protocol, transport, core, and TUI tests

## Why

Skill-triggered approvals already carry skill context inside core, but
app-server clients could not see which skill caused the prompt. Sending
the skill metadata with the approval request makes it possible for
clients to present better approval UX and connect the prompt back to the
relevant skill definition.


## example event in app-server-v2
verified that we see this event when experimental api is on:
```
< {
<   "id": 11,
<   "method": "item/commandExecution/requestApproval",
<   "params": {
<     "additionalPermissions": {
<       "fileSystem": null,
<       "macos": {
<         "accessibility": false,
<         "automations": {
<           "bundle_ids": [
<             "com.apple.Notes"
<           ]
<         },
<         "calendar": false,
<         "preferences": "read_only"
<       },
<       "network": null
<     },
<     "approvalId": "25d600ee-5a3c-4746-8d17-e2e61fb4c563",
<     "availableDecisions": [
<       "accept",
<       "acceptForSession",
<       "cancel"
<     ],
<     "command": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes/scripts/notes_info",
<     "commandActions": [
<       {
<         "command": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes/scripts/notes_info",
<         "type": "unknown"
<       }
<     ],
<     "cwd": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes",
<     "itemId": "call_jZp3xFpNg4D8iKAD49cvEvZy",
<     "skillMetadata": {
<       "pathToSkillsMd": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes/SKILL.md"
<     },
<     "threadId": "019ccc10-b7d3-7ff2-84fe-3a75e7681e69",
<     "turnId": "019ccc10-b848-76f1-81b3-4a1fa225493f"
<   }
< }`
```

& verified that this is the event when experimental api is off:
```
< {
<   "id": 13,
<   "method": "item/commandExecution/requestApproval",
<   "params": {
<     "approvalId": "5fbbf776-261b-4cf8-899b-c125b547f2c0",
<     "availableDecisions": [
<       "accept",
<       "acceptForSession",
<       "cancel"
<     ],
<     "command": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes/scripts/notes_info",
<     "commandActions": [
<       {
<         "command": "/Applications/ChatGPT.app/Contents/Resources/CodexAppServer_CodexAppServerBundledSkills.bundle/Contents/Resources/skills/apple-notes/scripts/notes_info",
<         "type": "unknown"
<       }
<     ],
<     "cwd": "/Users/celia/code/codex/codex-rs",
<     "itemId": "call_OV2DHzTgYcbYtWaTTBWlocOt",
<     "threadId": "019ccc16-2a2b-7be1-8500-e00d45b892d4",
<     "turnId": "019ccc16-2a8e-7961-98ec-649600e7d06a"
<   }
< }
```

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -1562,6 +1562,7 @@ mod tests {
                 }),
                 macos: None,
             }),
+            skill_metadata: None,
             proposed_execpolicy_amendment: None,
             proposed_network_policy_amendments: None,
             available_decisions: None,
@@ -1572,4 +1573,31 @@ mod tests {
             Some("item/commandExecution/requestApproval.additionalPermissions")
         );
     }
+
+    #[test]
+    fn command_execution_request_approval_skill_metadata_is_marked_experimental() {
+        let params = v2::CommandExecutionRequestApprovalParams {
+            thread_id: "thr_123".to_string(),
+            turn_id: "turn_123".to_string(),
+            item_id: "call_123".to_string(),
+            approval_id: None,
+            reason: None,
+            network_approval_context: None,
+            command: Some("cat file".to_string()),
+            cwd: None,
+            command_actions: None,
+            additional_permissions: None,
+            skill_metadata: Some(v2::CommandExecutionRequestApprovalSkillMetadata {
+                path_to_skills_md: PathBuf::from("/tmp/SKILLS.md"),
+            }),
+            proposed_execpolicy_amendment: None,
+            proposed_network_policy_amendments: None,
+            available_decisions: None,
+        };
+        let reason = crate::experimental_api::ExperimentalApi::experimental_reason(&params);
+        assert_eq!(
+            reason,
+            Some("item/commandExecution/requestApproval.skillMetadata")
+        );
+    }
 }

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -7,6 +7,7 @@ use crate::protocol::common::AuthMode;
 use codex_experimental_api_macros::ExperimentalApi;
 use codex_protocol::account::PlanType;
 use codex_protocol::approvals::ElicitationRequest as CoreElicitationRequest;
+use codex_protocol::approvals::ExecApprovalRequestSkillMetadata as CoreExecApprovalRequestSkillMetadata;
 use codex_protocol::approvals::ExecPolicyAmendment as CoreExecPolicyAmendment;
 use codex_protocol::approvals::NetworkApprovalContext as CoreNetworkApprovalContext;
 use codex_protocol::approvals::NetworkApprovalProtocol as CoreNetworkApprovalProtocol;
@@ -2827,6 +2828,14 @@ impl From<CoreSkillMetadata> for SkillMetadata {
     }
 }
 
+impl From<CoreExecApprovalRequestSkillMetadata> for CommandExecutionRequestApprovalSkillMetadata {
+    fn from(value: CoreExecApprovalRequestSkillMetadata) -> Self {
+        Self {
+            path_to_skills_md: value.path_to_skills_md,
+        }
+    }
+}
+
 impl From<CoreSkillInterface> for SkillInterface {
     fn from(value: CoreSkillInterface) -> Self {
         Self {
@@ -4300,6 +4309,11 @@ pub struct CommandExecutionRequestApprovalParams {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub additional_permissions: Option<AdditionalPermissionProfile>,
+    /// Optional skill metadata when the approval was triggered by a skill script.
+    #[experimental("item/commandExecution/requestApproval.skillMetadata")]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional = nullable)]
+    pub skill_metadata: Option<CommandExecutionRequestApprovalSkillMetadata>,
     /// Optional proposed execpolicy amendment to allow similar commands without prompting.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
@@ -4321,9 +4335,17 @@ impl CommandExecutionRequestApprovalParams {
         // We need a generic outbound compatibility design for stripping or
         // otherwise handling experimental server->client payloads.
         self.additional_permissions = None;
+        self.skill_metadata = None;
     }
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct CommandExecutionRequestApprovalSkillMetadata {
+    pub path_to_skills_md: PathBuf,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]
@@ -5098,6 +5120,7 @@ mod tests {
                 },
                 "macos": null
             },
+            "skillMetadata": null,
             "proposedExecpolicyAmendment": null,
             "proposedNetworkPolicyAmendments": null,
             "availableDecisions": null
@@ -5133,6 +5156,7 @@ mod tests {
                     "calendar": false
                 }
             },
+            "skillMetadata": null,
             "proposedExecpolicyAmendment": null,
             "proposedNetworkPolicyAmendments": null,
             "availableDecisions": null
@@ -5150,6 +5174,35 @@ mod tests {
         );
     }
 
+    #[test]
+    fn command_execution_request_approval_accepts_skill_metadata() {
+        let params = serde_json::from_value::<CommandExecutionRequestApprovalParams>(json!({
+            "threadId": "thr_123",
+            "turnId": "turn_123",
+            "itemId": "call_123",
+            "command": "cat file",
+            "cwd": "/tmp",
+            "commandActions": null,
+            "reason": null,
+            "networkApprovalContext": null,
+            "additionalPermissions": null,
+            "skillMetadata": {
+                "pathToSkillsMd": "/tmp/SKILLS.md"
+            },
+            "proposedExecpolicyAmendment": null,
+            "proposedNetworkPolicyAmendments": null,
+            "availableDecisions": null
+        }))
+        .expect("skill metadata should deserialize");
+
+        assert_eq!(
+            params.skill_metadata,
+            Some(CommandExecutionRequestApprovalSkillMetadata {
+                path_to_skills_md: PathBuf::from("/tmp/SKILLS.md"),
+            })
+        );
+    }
+
     #[test]
     fn command_exec_params_default_optional_streaming_flags() {
         let params = serde_json::from_value::<CommandExecParams>(json!({