bazel: lint rust_test targets in clippy workflow (#16450)

## Why

`cargo clippy --tests` was catching warnings in inline `#[cfg(test)]`
code that the Bazel PR Clippy lane missed. The existing Bazel invocation
linted `//codex-rs/...`, but that did not apply Clippy to the generated
manual `rust_test` binaries, so warnings in targets such as
`//codex-rs/state:state-unit-tests-bin` only surfaced as plain compile
warnings instead of failing the lint job.

## What Changed

- added `scripts/list-bazel-clippy-targets.sh` to expand the Bazel
Clippy target set with the generated manual `rust_test` rules while
still excluding `//codex-rs/v8-poc:all`
- updated `.github/workflows/bazel.yml` to use that expanded target list
in the Bazel Clippy PR job
- updated `just bazel-clippy` to use the same target expansion locally
- updated `.github/workflows/README.md` to document that the Bazel PR
lint lane now covers inline `#[cfg(test)]` code

## Verification

- `./scripts/list-bazel-clippy-targets.sh` includes
`//codex-rs/state:state-unit-tests-bin`
- `bazel build --config=clippy -- //codex-rs/state:state-unit-tests-bin`
now fails with the same unused import in `state/src/runtime/logs.rs`
that `cargo clippy --tests` reports

scripts/list-bazel-clippy-targets.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${repo_root}"
+
+# Resolve the dynamic targets before printing anything so callers do not
+# continue with a partial list if `bazel query` fails.
+manual_rust_test_targets="$(bazel query 'kind("rust_test rule", attr(tags, "manual", //codex-rs/... except //codex-rs/v8-poc/...))')"
+
+printf '%s\n' \
+  "//codex-rs/..." \
+  "-//codex-rs/v8-poc:all"
+
+# `--config=clippy` on the `workspace_root_test` wrappers does not lint the
+# underlying `rust_test` binaries. Add the internal manual `*-unit-tests-bin`
+# targets explicitly so inline `#[cfg(test)]` code is linted like
+# `cargo clippy --tests`.
+printf '%s\n' "${manual_rust_test_targets}"