[docs] Revert extra changes from PR 17848 (#18003)

## Summary

1. Revert https://github.com/openai/codex/pull/17848 so the Bazel and
`BUILD` file changes leave `main`.
2. Prepare for a narrower follow up that restores only `SECURITY.md`.

## Validation

1. Reviewed the revert diff against `main`.
2. Ran a clean diff check before push.

codex-rs/app-server/BUILD.bazel

@@ -3,9 +3,6 @@ load("//:defs.bzl", "codex_rust_crate")
 codex_rust_crate(
     name = "app-server",
     crate_name = "codex_app_server",
-    integration_test_tags_extra_by_stem = {
-        "all": ["flaky"],
-    },
     integration_test_timeout = "long",
     test_tags = ["no-sandbox"],
 )