Recognize MCP tool hook configurations (#37363)

## What changed

- Parse `mcp_tool` hook handlers with a server, tool, JSON input, and optional timeout and status message.
- Return managed MCP tool hooks from `configRequirements/read` and include the handler in the generated protocol schemas.
- Skip MCP tool hooks during discovery with an explicit warning until execution is supported.

## Testing

- Cover MCP tool hook deserialization, including nested and null JSON input values.
- Extend the config requirements RPC test to verify the new handler shape.

GitOrigin-RevId: ff7e2d12b75b486c54d63469af547a29f9b31418

codex-rs/app-server-protocol/src/protocol/v2/config.rs

@@ -519,6 +519,19 @@ pub enum ConfiguredHookHandler {
         #[ts(rename = "additionalContextLimit")]
         additional_context_limit: Option<usize>,
     },
+    #[serde(rename = "mcp_tool")]
+    #[ts(rename = "mcp_tool")]
+    McpTool {
+        server: String,
+        tool: String,
+        input: serde_json::Map<String, serde_json::Value>,
+        #[serde(rename = "timeoutSec")]
+        #[ts(rename = "timeoutSec")]
+        timeout_sec: Option<u64>,
+        #[serde(rename = "statusMessage")]
+        #[ts(rename = "statusMessage")]
+        status_message: Option<String>,
+    },
     #[serde(rename = "prompt")]
     #[ts(rename = "prompt")]
     Prompt {},