app-server: Replay pending item requests on thread/resume (#12560)

Replay pending client requests after `thread/resume` and emit resolved
notifications when those requests clear so approval/input UI state stays
in sync after reconnects and across subscribed clients.

Affected RPCs:
- `item/commandExecution/requestApproval`
- `item/fileChange/requestApproval`
- `item/tool/requestUserInput`

Motivation:
- Resumed clients need to see pending approval/input requests that were
already outstanding before the reconnect.
- Clients also need an explicit signal when a pending request resolves
or is cleared so stale UI can be removed on turn start, completion, or
interruption.

Implementation notes:
- Use pending client requests from `OutgoingMessageSender` in order to
replay them after `thread/resume` attaches the connection, using
original request ids.
- Emit `serverRequest/resolved` when pending requests are answered
or cleared by lifecycle cleanup.
- Update the app-server protocol schema, generated TypeScript bindings,
and README docs for the replay/resolution flow.

High-level test plan:
- Added automated coverage for replaying pending command execution and
file change approval requests on `thread/resume`.
- Added automated coverage for resolved notifications in command
approval, file change approval, request_user_input, turn start, and turn
interrupt flows.
- Verified schema/docs updates in the relevant protocol and app-server
tests.

Manual testing:
- Tested reconnect/resume with multiple connections.
- Confirmed state stayed in sync between connections.

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

@@ -548,6 +548,14 @@ macro_rules! server_request_definitions {
             )*
         }
 
+        impl ServerRequest {
+            pub fn id(&self) -> &RequestId {
+                match self {
+                    $(Self::$variant { request_id, .. } => request_id,)*
+                }
+            }
+        }
+
         #[derive(Debug, Clone, PartialEq, JsonSchema)]
         #[allow(clippy::large_enum_variant)]
         pub enum ServerRequestPayload {
@@ -838,6 +846,7 @@ server_notification_definitions! {
     CommandExecutionOutputDelta => "item/commandExecution/outputDelta" (v2::CommandExecutionOutputDeltaNotification),
     TerminalInteraction => "item/commandExecution/terminalInteraction" (v2::TerminalInteractionNotification),
     FileChangeOutputDelta => "item/fileChange/outputDelta" (v2::FileChangeOutputDeltaNotification),
+    ServerRequestResolved => "serverRequest/resolved" (v2::ServerRequestResolvedNotification),
     McpToolCallProgress => "item/mcpToolCall/progress" (v2::McpToolCallProgressNotification),
     McpServerOauthLoginCompleted => "mcpServer/oauthLogin/completed" (v2::McpServerOauthLoginCompletedNotification),
     AccountUpdated => "account/updated" (v2::AccountUpdatedNotification),
@@ -1106,6 +1115,7 @@ mod tests {
         );
 
         let payload = ServerRequestPayload::ExecCommandApproval(params);
+        assert_eq!(request.id(), &RequestId::Integer(7));
         assert_eq!(payload.request_with_id(RequestId::Integer(7)), request);
         Ok(())
     }