Add opt-in MCP user-verification transport (#43352)

## Why

Device-authenticated verification needs an app response outside automated approval and review. Previously, MCP user-verification requests were always cancelled.

## What changed

- Add typed `openai/userVerification` elicitations carrying a title, description, and challenge through core and app-server.
- Route verification to one connection enabled by trusted host activation. Restrict responses to that owner, exclude requests from replay, and cancel on disconnect or authentication changes, including account switches away and back.
- Return proofs in `content`, discard response metadata, and cancel malformed acceptances. Suppress verification response logging and analytics, and send only a generic verification notice to realtime.
- Keep the mode experimental and exclude it from stable schema exports. Capability advertisement remains disabled, and the TUI cancels verification requests.

## Testing

Add coverage for owner isolation, disconnect and authentication races, proof response handling, automated-review bypass, inactive-host cancellation, stable schema filtering, and realtime payload exclusion. Update the MCP integration test to verify that an activated request holds the tool until the client responds.

GitOrigin-RevId: c8c7b6691a3f7756682bbcca9def1df0d1feb906

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

@@ -39,6 +39,9 @@ use std::path::PathBuf;
 use std::process::Command;
 use std::thread;
 
+#[path = "export_user_verification.rs"]
+mod user_verification;
+
 pub(crate) const GENERATED_TS_HEADER: &str = "// GENERATED CODE! DO NOT MODIFY BY HAND!\n\n";
 const IGNORED_DEFINITIONS: &[&str] = &["Option<()>"];
 const JSON_V1_ALLOWLIST: &[&str] = &["InitializeParams", "InitializeResponse"];
@@ -271,6 +274,11 @@ fn filter_experimental_ts(out_dir: &Path) -> Result<()> {
     filter_request_ts(out_dir, "ServerRequest.ts", EXPERIMENTAL_SERVER_METHODS)?;
     filter_experimental_type_fields_ts(out_dir, &registered_fields)?;
     remove_generated_type_files(out_dir, &experimental_method_types, "ts")?;
+    let elicitation_path = out_dir.join("v2/McpServerElicitationRequestParams.ts");
+    if elicitation_path.exists() {
+        let content = fs::read_to_string(&elicitation_path)?;
+        fs::write(elicitation_path, user_verification::filter_ts(&content))?;
+    }
     Ok(())
 }
 
@@ -295,6 +303,11 @@ pub(crate) fn filter_experimental_ts_tree(tree: &mut BTreeMap<PathBuf, String>)
     }
 
     for (path, content) in tree.iter_mut() {
+        if path.file_stem().and_then(|stem| stem.to_str())
+            == Some("McpServerElicitationRequestParams")
+        {
+            *content = user_verification::filter_ts(content);
+        }
         let Some(type_name) = path.file_stem().and_then(|stem| stem.to_str()) else {
             continue;
         };
@@ -339,7 +352,7 @@ fn filter_request_ts_contents(mut content: String, experimental_methods: &[&str]
     let filtered_arms: Vec<String> = arms
         .into_iter()
         .filter(|arm| {
-            extract_method_from_arm(arm)
+            extract_discriminator_from_arm(arm, "method")
                 .is_none_or(|method| !experimental_methods.contains(method.as_str()))
         })
         .collect();
@@ -425,6 +438,7 @@ fn filter_experimental_schema(bundle: &mut Value) -> Result<()> {
     prune_experimental_methods(bundle, EXPERIMENTAL_CLIENT_METHODS);
     prune_experimental_methods(bundle, EXPERIMENTAL_SERVER_METHODS);
     remove_experimental_method_type_definitions(bundle);
+    user_verification::filter_json(bundle);
     Ok(())
 }
 
@@ -804,14 +818,14 @@ fn split_top_level_multi(input: &str, delimiters: &[char]) -> Vec<String> {
     parts
 }
 
-fn extract_method_from_arm(arm: &str) -> Option<String> {
+fn extract_discriminator_from_arm(arm: &str, discriminator: &str) -> Option<String> {
     let (open, close) = find_top_level_brace_span(arm)?;
     let inner = &arm[open + 1..close];
     for field in split_top_level(inner, ',') {
         let Some((name, value)) = parse_property(field.as_str()) else {
             continue;
         };
-        if name != "method" {
+        if name != discriminator {
             continue;
         }
         let value = value.trim_start();