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-protocol/schema/json/ServerRequest.json

@@ -340,11 +340,22 @@
     },
     "CommandExecutionApprovalKind": {
       "description": "Distinguishes a command approval from input sent to an existing terminal.",
-      "enum": [
-        "command",
-        "writeStdin"
-      ],
-      "type": "string"
+      "oneOf": [
+        {
+          "enum": [
+            "command",
+            "writeStdin"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "A managed checkpoint requiring a fresh human decision. Only `accept`, `decline`, and `cancel` are valid. Requires the `requiredHumanApproval` initialize capability. This prompt does not itself start a command execution item.",
+          "enum": [
+            "humanCommand"
+          ],
+          "type": "string"
+        }
+      ]
     },
     "CommandExecutionRequestApprovalParams": {
       "properties": {