Expose MCP app identity in app context (#29934)

## Why

MCP tool-call events need to expose trusted app identity and action
metadata directly so v2 clients do not have to infer it from tool names
or resource URIs.

## What changed

- Add optional `appName`, `templateId`, and `actionName` fields to MCP
tool-call `appContext`.
- Populate `appName` and `templateId` from trusted Codex Apps metadata,
and derive `actionName` from the trusted app resource metadata.
- Preserve all three fields through core events, legacy protocol events,
persisted thread history, resume redaction, and app-server v2 responses.
- Document the public `appContext` fields in
`codex-rs/app-server/README.md`.
- Regenerate app-server JSON and TypeScript schemas and add coverage for
serialization, persistence, redaction, and metadata propagation.

## Validation

- `just test -p codex-app-server-protocol mcp_tool_call`
- `just test -p codex-core
mcp_tool_call_item_metadata_only_trusts_codex_apps_identity
mcp_tool_call_item_includes_app_identity`
- `just write-app-server-schema`

---------

Co-authored-by: Martin Au-Yeung <280153141+martinauyeung-oai@users.noreply.github.com>

codex-rs/app-server/README.md

@@ -1372,7 +1372,7 @@ Today both notifications carry an empty `items` array even when item events were
 - `reasoning` — `{id, summary, content}` where `summary` holds streamed reasoning summaries (applicable for most OpenAI models) and `content` holds raw reasoning blocks (applicable for e.g. open source models).
 - `commandExecution` — `{id, command, cwd, status, commandActions, aggregatedOutput?, exitCode?, durationMs?}` for sandboxed commands; `status` is `inProgress`, `completed`, `failed`, or `declined`.
 - `fileChange` — `{id, changes, status}` describing proposed edits; `changes` list `{path, kind, diff}` and `status` is `inProgress`, `completed`, `failed`, or `declined`.
-- `mcpToolCall` — `{id, server, tool, status, arguments, appContext, mcpAppResourceUri?, pluginId, result?, error?}` describing MCP calls; `appContext` is `{connectorId, linkId, resourceUri}` for calls through a trusted MCP app, where `connectorId` identifies the connector that owns the tool, `linkId` identifies the app link, and `resourceUri` points to the widget template. The top-level `mcpAppResourceUri` is deprecated and temporarily duplicated for client migration. `tool` identifies the invoked action. `status` is `inProgress`, `completed`, or `failed`.
+- `mcpToolCall` — `{id, server, tool, status, arguments, appContext, mcpAppResourceUri?, pluginId, result?, error?}` describing MCP calls; `appContext` is `{connectorId, linkId, resourceUri, appName, templateId, actionName}` for calls through a trusted MCP app, where `connectorId` identifies the connector that owns the tool, `linkId` identifies the app link, `resourceUri` points to the widget template, `appName` is the connector's display name, `templateId` identifies the app template, and `actionName` is the stable connector `Action.name`. `appName`, `templateId`, and `actionName` may be null for older rollout entries. The top-level `mcpAppResourceUri` is deprecated and temporarily duplicated for client migration. `tool` identifies the raw MCP tool. `status` is `inProgress`, `completed`, or `failed`.
 - `collabToolCall` — `{id, tool, status, senderThreadId, receiverThreadId?, newThreadId?, prompt?, agentStatus?}` describing collab tool calls (`spawn_agent`, `send_input`, `resume_agent`, `wait`, `close_agent`); `status` is `inProgress`, `completed`, or `failed`.
 - `webSearch` — `{id, query, action?}` for a web search request issued by the agent; `action` mirrors the Responses API web_search action payload (`search`, `open_page`, `find_in_page`) and may be omitted until completion.
 - `imageView` — `{id, path}` emitted when the agent invokes the image viewer tool.

codex-rs/app-server/src/request_processors/thread_resume_redaction.rs

@@ -83,6 +83,9 @@ mod tests {
                     connector_id: "calendar".to_string(),
                     link_id: Some("link_calendar".to_string()),
                     resource_uri: Some("ui://widget/lookup.html".to_string()),
+                    app_name: Some("Calendar".to_string()),
+                    template_id: Some("calendar_template".to_string()),
+                    action_name: Some("lookup".to_string()),
                 }),
                 mcp_app_resource_uri: Some("ui://widget/lookup.html".to_string()),
                 plugin_id: Some("sample@test".to_string()),
@@ -130,6 +133,9 @@ mod tests {
                     connector_id: "calendar".to_string(),
                     link_id: Some("link_calendar".to_string()),
                     resource_uri: Some("ui://widget/lookup.html".to_string()),
+                    app_name: Some("Calendar".to_string()),
+                    template_id: Some("calendar_template".to_string()),
+                    action_name: Some("lookup".to_string()),
                 }),
                 mcp_app_resource_uri: Some("ui://widget/lookup.html".to_string()),
                 plugin_id: Some("sample@test".to_string()),

codex-rs/app-server/tests/suite/v2/thread_resume.rs

@@ -834,6 +834,9 @@ async fn thread_resume_redacts_payloads_for_chatgpt_remote_clients() -> Result<(
                     connector_id: "calendar".to_string(),
                     link_id: Some("link_calendar".to_string()),
                     resource_uri: Some("ui://widget/lookup.html".to_string()),
+                    app_name: Some("Calendar".to_string()),
+                    template_id: Some("calendar_template".to_string()),
+                    action_name: Some("lookup".to_string()),
                 })
             );
             let result = result.as_ref().expect("redacted MCP result");
@@ -884,6 +887,9 @@ async fn thread_resume_redacts_payloads_for_chatgpt_remote_clients() -> Result<(
             connector_id: "calendar".to_string(),
             link_id: Some("link_calendar".to_string()),
             resource_uri: Some("ui://widget/lookup.html".to_string()),
+            app_name: Some("Calendar".to_string()),
+            template_id: Some("calendar_template".to_string()),
+            action_name: Some("lookup".to_string()),
         })
     );
     let result = result.as_ref().expect("normal MCP result");
@@ -990,6 +996,9 @@ fn append_resume_redaction_history(
             connector_id: Some("calendar".to_string()),
             mcp_app_resource_uri: Some("ui://widget/lookup.html".to_string()),
             link_id: Some("link_calendar".to_string()),
+            app_name: Some("Calendar".to_string()),
+            template_id: Some("calendar_template".to_string()),
+            action_name: Some("lookup".to_string()),
             plugin_id: None,
             duration: Duration::from_millis(8),
             result: Ok(CallToolResult {