Add managed command checkpoints requiring fresh human approval (#58045)

## Why

Managed command policies need to require a human decision independently of automatic review, hook allowances, and saved approvals.

## What changed

- Support `decision = "prompt-user"` in managed `requirements.toml` prefix rules, requiring a fresh, one-time human decision for matching commands.
- Add experimental `humanCommand` approval requests for clients advertising both `experimentalApi` and `requiredHumanApproval`. Accept only `accept`, `decline`, or `cancel`; reject commands when no capable client is available.
- Restrict responses to capable clients that received the request, and replay pending prompts to compatible clients on reconnect.
- Enable the capability in the TUI and update protocol schemas and client bindings.

## Testing

Add coverage for fresh decisions overriding saved allowances, hook allowances, and automatic review, plus child-thread approval routing and rejection of responses from incompatible or unrelated clients.

GitOrigin-RevId: 0b95ff6aab7f8a04b7298c8a4329d1fddf6a603e

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

@@ -141,6 +141,11 @@ impl InitializeRequestProcessor {
         {
             return Err(invalid_request("Already initialized"));
         }
+        if experimental_api_enabled && capabilities.required_human_approval {
+            self.outgoing
+                .enable_human_approval_connection(connection_id)
+                .await;
+        }
         if user_verification_enabled {
             self.outgoing
                 .enable_user_verification_connection(connection_id)