feat(core): add watchdog runtime and prompts

Preserve the watchdog runtime and prompt behavior on top of the refreshed inbox branch and collapse the branch back to a single commit for easier future restacks.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/mcp-server/tests/suite/codex_tool.rs

@@ -426,7 +426,9 @@ async fn codex_tool_passes_base_instructions() -> anyhow::Result<()> {
         "expected permissions developer message, got {developer_contents:?}"
     );
     assert!(
-        developer_contents.contains(&"Foreshadow upcoming tool calls."),
+        developer_contents
+            .iter()
+            .any(|content| content.contains("Foreshadow upcoming tool calls.")),
         "expected developer instructions in developer messages, got {developer_contents:?}"
     );