[codex] Revert shared BuildBuddy Bazel wrapper (#25909)

## Why

PR #25905 intentionally adds a failing `codex-core` unit test, but its
[Bazel test on Windows
check](https://github.com/openai/codex/actions/runs/26837526950/job/79135369259)
passed. That shows the Bazel configuration introduced by #25156 is not
behaving as expected, so revert it while the configuration can be
investigated separately.

## What changed

Revert #25156 in full, restoring the previous Bazel remote
configuration, CI scripts, workflows, `rusty_v8` handling, and
documentation. This removes the shared BuildBuddy wrapper and its tests.

## Validation

Not run locally; this exact revert was prioritized for a fast rollback.

scripts/list-bazel-clippy-targets.sh

@@ -20,13 +20,23 @@ while [[ $# -gt 0 ]]; do
 done
 
 # Resolve the dynamic targets before printing anything so callers do not
-# continue with a partial list if `bazel query` fails. Target discovery is
-# local on all platforms.
-manual_rust_test_targets="$(
-  ./.github/scripts/run-bazel-query-ci.sh \
-    --output=label \
-    -- 'kind("rust_test rule", attr(tags, "manual", //codex-rs/... except //codex-rs/v8-poc/...))'
-)"
+# continue with a partial list if `bazel query` fails. Reuse the same CI Bazel
+# server settings as the subsequent build so Windows jobs do not cold-start a
+# second Bazel server just for target discovery.
+if [[ $windows_cross_compile -eq 1 ]]; then
+  manual_rust_test_targets="$(
+    ./.github/scripts/run-bazel-query-ci.sh \
+      --windows-cross-compile \
+      --output=label \
+      -- 'kind("rust_test rule", attr(tags, "manual", //codex-rs/... except //codex-rs/v8-poc/...))'
+  )"
+else
+  manual_rust_test_targets="$(
+    ./.github/scripts/run-bazel-query-ci.sh \
+      --output=label \
+      -- 'kind("rust_test rule", attr(tags, "manual", //codex-rs/... except //codex-rs/v8-poc/...))'
+  )"
+fi
 if [[ "${RUNNER_OS:-}" != "Windows" ]]; then
   # Non-Windows clippy jobs lint the native test binaries; the
   # Windows-cross binaries exist only for the fast Windows test leg.