Use released DotSlash package for argument-comment lint (#15199)

## Why
The argument-comment lint now has a packaged DotSlash artifact from
[#15198](https://github.com/openai/codex/pull/15198), so the normal repo
lint path should use that released payload instead of rebuilding the
lint from source every time.

That keeps `just clippy` and CI aligned with the shipped artifact while
preserving a separate source-build path for people actively hacking on
the lint crate.

The current alpha package also exposed two integration wrinkles that the
repo-side prebuilt wrapper needs to smooth over:
- the bundled Dylint library filename includes the host triple, for
example `@nightly-2025-09-18-aarch64-apple-darwin`, and Dylint derives
`RUSTUP_TOOLCHAIN` from that filename
- on Windows, Dylint's driver path also expects `RUSTUP_HOME` to be
present in the environment

Without those adjustments, the prebuilt CI jobs fail during `cargo
metadata` or driver setup. This change makes the checked-in prebuilt
wrapper normalize the packaged library name to the plain
`nightly-2025-09-18` channel before invoking `cargo-dylint`, and it
teaches both the wrapper and the packaged runner source to infer
`RUSTUP_HOME` from `rustup show home` when the environment does not
already provide it.

After the prebuilt Windows lint job started running successfully, it
also surfaced a handful of existing anonymous literal callsites in
`windows-sandbox-rs`. This PR now annotates those callsites so the new
cross-platform lint job is green on the current tree.

## What Changed
- checked in the current
`tools/argument-comment-lint/argument-comment-lint` DotSlash manifest
- kept `tools/argument-comment-lint/run.sh` as the source-build wrapper
for lint development
- added `tools/argument-comment-lint/run-prebuilt-linter.sh` as the
normal enforcement path, using the checked-in DotSlash package and
bundled `cargo-dylint`
- updated `just clippy` and `just argument-comment-lint` to use the
prebuilt wrapper
- split `.github/workflows/rust-ci.yml` so source-package checks live in
a dedicated `argument_comment_lint_package` job, while the released lint
runs in an `argument_comment_lint_prebuilt` matrix on Linux, macOS, and
Windows
- kept the pinned `nightly-2025-09-18` toolchain install in the prebuilt
CI matrix, since the prebuilt package still relies on rustup-provided
toolchain components
- updated `tools/argument-comment-lint/run-prebuilt-linter.sh` to
normalize host-qualified nightly library filenames, keep the `rustup`
shim directory ahead of direct toolchain `cargo` binaries, and export
`RUSTUP_HOME` when needed for Windows Dylint driver setup
- updated `tools/argument-comment-lint/src/bin/argument-comment-lint.rs`
so future published DotSlash artifacts apply the same nightly-filename
normalization and `RUSTUP_HOME` inference internally
- fixed the remaining Windows lint violations in
`codex-rs/windows-sandbox-rs` by adding the required `/*param*/`
comments at the reported callsites
- documented the checked-in DotSlash file, wrapper split, archive
layout, nightly prerequisite, and Windows `RUSTUP_HOME` requirement in
`tools/argument-comment-lint/README.md`

tools/argument-comment-lint/README.md

@@ -73,21 +73,71 @@ GitHub releases also publish a DotSlash file named
 x64. The published package contains a small runner executable, a bundled
 `cargo-dylint`, and the prebuilt lint library.
 
-Run the lint against `codex-rs` from the repo root:
+The package is not a full Rust toolchain. Running the prebuilt path still
+requires the pinned nightly toolchain to be installed via `rustup`:
+
+```bash
+rustup toolchain install nightly-2025-09-18 \
+  --component llvm-tools-preview \
+  --component rustc-dev \
+  --component rust-src
+```
+
+The checked-in DotSlash file lives at `tools/argument-comment-lint/argument-comment-lint`.
+`run-prebuilt-linter.sh` resolves that file via `dotslash` and is the path used by
+`just clippy`, `just argument-comment-lint`, and the Rust CI job. The
+source-build path remains available in `run.sh` for people
+iterating on the lint crate itself.
+
+The Unix archive layout is:
+
+```text
+argument-comment-lint/
+  bin/
+    argument-comment-lint
+    cargo-dylint
+  lib/
+    libargument_comment_lint@nightly-2025-09-18-<target>.dylib|so
+```
+
+On Windows the same layout is published as a `.zip`, with `.exe` and `.dll`
+filenames instead.
+
+DotSlash resolves the package entrypoint to `argument-comment-lint/bin/argument-comment-lint`
+(or `.exe` on Windows). That runner finds the sibling bundled `cargo-dylint`
+binary and the single packaged Dylint library under `lib/`, normalizes the
+host-qualified nightly filename to the plain `nightly-2025-09-18` channel when
+needed, and then invokes `cargo-dylint dylint --lib-path <that-library>` with
+the repo's default `DYLINT_RUSTFLAGS` and `CARGO_INCREMENTAL=0` settings.
+
+The checked-in `run-prebuilt-linter.sh` wrapper uses the fetched package
+contents directly so the current checked-in alpha artifact works the same way.
+It also makes sure the `rustup` shims stay ahead of any direct toolchain
+`cargo` binary on `PATH`, and sets `RUSTUP_HOME` from `rustup show home` when
+the environment does not already provide it. That extra `RUSTUP_HOME` export is
+required for the current Windows Dylint driver path.
+
+If you are changing the lint crate itself, use the source-build wrapper:
 
 ```bash
 ./tools/argument-comment-lint/run.sh -p codex-core
+```
+
+Run the lint against `codex-rs` from the repo root:
+
+```bash
+./tools/argument-comment-lint/run-prebuilt-linter.sh -p codex-core
 just argument-comment-lint -p codex-core
 ```
 
-If no package selection is provided, `run.sh` defaults to checking the
+If no package selection is provided, `run-prebuilt-linter.sh` defaults to checking the
 `codex-rs` workspace with `--workspace --no-deps`.
 
 Repo runs also promote `uncommented_anonymous_literal_argument` to an error by
 default:
 
 ```bash
-./tools/argument-comment-lint/run.sh -p codex-core
+./tools/argument-comment-lint/run-prebuilt-linter.sh -p codex-core
 ```
 
 The wrapper does that by setting `DYLINT_RUSTFLAGS`, and it leaves an explicit
@@ -105,5 +155,5 @@ CARGO_INCREMENTAL=1 \
 To expand target coverage for an ad hoc run:
 
 ```bash
-./tools/argument-comment-lint/run.sh -p codex-core -- --all-targets
+./tools/argument-comment-lint/run-prebuilt-linter.sh -p codex-core -- --all-targets
 ```