Add js_repl host helpers and exec end events (#10672)

## Summary

This PR adds host-integrated helper APIs for `js_repl` and updates model
guidance so the agent can use them reliably.

### What’s included

- Add `codex.tool(name, args?)` in the JS kernel so `js_repl` can call
normal Codex tools.
- Keep persistent JS state and scratch-path helpers available:
  - `codex.state`
  - `codex.tmpDir`
- Wire `js_repl` tool calls through the standard tool router path.
- Add/align `js_repl` execution completion/end event behavior with
existing tool logging patterns.
- Update dynamic prompt injection (`project_doc`) to document:
  - how to call `codex.tool(...)`
  - raw output behavior
- image flow via `view_image` (`codex.tmpDir` +
`codex.tool("view_image", ...)`)
- stdio safety guidance (`console.log` / `codex.tool`, avoid direct
`process.std*`)

## Why

- Standardize JS-side tool usage on `codex.tool(...)`
- Make `js_repl` behavior more consistent with existing tool execution
and event/logging patterns.
- Give the model enough runtime guidance to use `js_repl` safely and
effectively.

## Testing

- Added/updated unit and runtime tests for:
  - `codex.tool` calls from `js_repl` (including shell/MCP paths)
  - image handoff flow via `view_image`
  - prompt-injection text for `js_repl` guidance
  - execution/end event behavior and related regression coverage




#### [git stack](https://github.com/magus/git-stack-cli)
- ✅ `1` https://github.com/openai/codex/pull/10674
- 👉 `2` https://github.com/openai/codex/pull/10672
- ⏳ `3` https://github.com/openai/codex/pull/10671
- ⏳ `4` https://github.com/openai/codex/pull/10673
- ⏳ `5` https://github.com/openai/codex/pull/10670

codex-rs/core/src/project_doc.rs

@@ -42,13 +42,13 @@ fn render_js_repl_instructions(config: &Config) -> Option<String> {
     let mut section = String::from("## JavaScript REPL (Node)\n");
     section.push_str("- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel. `codex.state` persists for the session (best effort) and is cleared by `js_repl_reset`.\n");
     section.push_str("- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n");
-    section.push_str("- Helpers available in `js_repl`: `codex.state` and `codex.tmpDir`.\n");
+    section.push_str("- Helpers: `codex.state`, `codex.tmpDir`, and `codex.tool(name, args?)`.\n");
+    section.push_str("- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike.\n");
+    section.push_str("- To share generated images with the model, write a file under `codex.tmpDir`, call `await codex.tool(\"view_image\", { path: \"/absolute/path\" })`, then delete the file.\n");
     section.push_str("- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n");
     section.push_str("- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n");
 
-    section.push_str(
-        "- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`.",
-    );
+    section.push_str("- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log` and `codex.tool(...)`.");
 
     Some(section)
 }
@@ -409,7 +409,7 @@ mod tests {
         let res = get_user_instructions(&cfg, None)
             .await
             .expect("js_repl instructions expected");
-        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel. `codex.state` persists for the session (best effort) and is cleared by `js_repl_reset`.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers available in `js_repl`: `codex.state` and `codex.tmpDir`.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`.";
+        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel. `codex.state` persists for the session (best effort) and is cleared by `js_repl_reset`.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.state`, `codex.tmpDir`, and `codex.tool(name, args?)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike.\n- To share generated images with the model, write a file under `codex.tmpDir`, call `await codex.tool(\"view_image\", { path: \"/absolute/path\" })`, then delete the file.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log` and `codex.tool(...)`.";
         assert_eq!(res, expected);
     }