fix: pin inputs (#17471)

## Summary
- Pin Rust git patch dependencies to immutable revisions and make
cargo-deny reject unknown git and registry sources unless explicitly
allowlisted.
- Add checked-in SHA-256 coverage for the current rusty_v8 release
assets, wire those hashes into Bazel, and verify CI override downloads
before use.
- Add rusty_v8 MODULE.bazel update/check tooling plus a Bazel CI guard
so future V8 bumps cannot drift from the checked-in checksum manifest.
- Pin release/lint cargo installs and all external GitHub Actions refs
to immutable inputs.

## Future V8 bump flow
Run these after updating the resolved `v8` crate version and checksum
manifest:

```bash
python3 .github/scripts/rusty_v8_bazel.py update-module-bazel
python3 .github/scripts/rusty_v8_bazel.py check-module-bazel
```

The update command rewrites the matching `rusty_v8_<crate_version>`
`http_file` SHA-256 values in `MODULE.bazel` from
`third_party/v8/rusty_v8_<crate_version>.sha256`. The check command is
also wired into Bazel CI to block drift.

## Notes
- This intentionally excludes RustSec dependency upgrades and
bubblewrap-related changes per request.
- The branch was rebased onto the latest origin/main before opening the
PR.

## Validation
- cargo fetch --locked
- cargo deny check advisories
- cargo deny check
- cargo deny check sources
- python3 .github/scripts/rusty_v8_bazel.py check-module-bazel
- python3 .github/scripts/rusty_v8_bazel.py update-module-bazel
- python3 -m unittest discover -s .github/scripts -p
'test_rusty_v8_bazel.py'
- python3 -m py_compile .github/scripts/rusty_v8_bazel.py
.github/scripts/rusty_v8_module_bazel.py
.github/scripts/test_rusty_v8_bazel.py
- repo-wide GitHub Actions `uses:` audit: all external action refs are
pinned to 40-character SHAs
- yq eval on touched workflows and local actions
- git diff --check
- just bazel-lock-check

## Hash verification
- Confirmed `MODULE.bazel` hashes match
`third_party/v8/rusty_v8_146_4_0.sha256`.
- Confirmed GitHub release asset digests for denoland/rusty_v8
`v146.4.0` and openai/codex `rusty-v8-v146.4.0` match the checked-in
hashes.
- Streamed and SHA-256 hashed all 10 `MODULE.bazel` rusty_v8 asset URLs
locally; every downloaded byte stream matched both `MODULE.bazel` and
the checked-in manifest.

## Pin verification
- Confirmed signing-action pins match the peeled commits for their tag
comments: `sigstore/cosign-installer@v3.7.0`, `azure/login@v2`, and
`azure/trusted-signing-action@v0`.
- Pinned the remaining tag-based action refs in Bazel CI/setup:
`actions/setup-node@v6`, `facebook/install-dotslash@v2`,
`bazelbuild/setup-bazelisk@v3`, and `actions/cache/restore@v5`.
- Normalized all `bazelbuild/setup-bazelisk@v3` refs to the peeled
commit behind the annotated tag.
- Audited Cargo git dependencies: every manifest git dependency uses
`rev` only, every `Cargo.lock` git source has `?rev=<sha>#<same-sha>`,
and `cargo deny check sources` passes with `required-git-spec = "rev"`.
- Shallow-fetched each distinct git dependency repo at its pinned SHA
and verified Git reports each object as a commit.

MODULE.bazel

@@ -423,6 +423,7 @@ http_archive(
 http_file(
     name = "rusty_v8_146_4_0_aarch64_apple_darwin_archive",
     downloaded_file_path = "librusty_v8_release_aarch64-apple-darwin.a.gz",
+    sha256 = "bfe2c9be32a56c28546f0f965825ee68fbf606405f310cc4e17b448a568cf98a",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/librusty_v8_release_aarch64-apple-darwin.a.gz",
     ],
@@ -431,6 +432,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_aarch64_unknown_linux_gnu_archive",
     downloaded_file_path = "librusty_v8_release_aarch64-unknown-linux-gnu.a.gz",
+    sha256 = "dbf165b07c81bdb054bc046b43d23e69fcf7bcc1a4c1b5b4776983a71062ecd8",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/librusty_v8_release_aarch64-unknown-linux-gnu.a.gz",
     ],
@@ -439,6 +441,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_aarch64_pc_windows_msvc_archive",
     downloaded_file_path = "rusty_v8_release_aarch64-pc-windows-msvc.lib.gz",
+    sha256 = "ed13363659c6d08583ac8fdc40493445c5767d8b94955a4d5d7bb8d5a81f6bf8",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/rusty_v8_release_aarch64-pc-windows-msvc.lib.gz",
     ],
@@ -447,6 +450,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_x86_64_apple_darwin_archive",
     downloaded_file_path = "librusty_v8_release_x86_64-apple-darwin.a.gz",
+    sha256 = "630cd240f1bbecdb071417dc18387ab81cf67c549c1c515a0b4fcf9eba647bb7",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/librusty_v8_release_x86_64-apple-darwin.a.gz",
     ],
@@ -455,6 +459,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_x86_64_unknown_linux_gnu_archive",
     downloaded_file_path = "librusty_v8_release_x86_64-unknown-linux-gnu.a.gz",
+    sha256 = "e64b4d99e4ae293a2e846244a89b80178ba10382c13fb591c1fa6968f5291153",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/librusty_v8_release_x86_64-unknown-linux-gnu.a.gz",
     ],
@@ -463,6 +468,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_x86_64_pc_windows_msvc_archive",
     downloaded_file_path = "rusty_v8_release_x86_64-pc-windows-msvc.lib.gz",
+    sha256 = "90a9a2346acd3685a355e98df85c24dbe406cb124367d16259a4b5d522621862",
     urls = [
         "https://github.com/denoland/rusty_v8/releases/download/v146.4.0/rusty_v8_release_x86_64-pc-windows-msvc.lib.gz",
     ],
@@ -471,6 +477,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_aarch64_unknown_linux_musl_archive",
     downloaded_file_path = "librusty_v8_release_aarch64-unknown-linux-musl.a.gz",
+    sha256 = "27a08ed26c34297bfd93e514692ccc44b85f8b15c6aa39cf34e784f84fb37e8e",
     urls = [
         "https://github.com/openai/codex/releases/download/rusty-v8-v146.4.0/librusty_v8_release_aarch64-unknown-linux-musl.a.gz",
     ],
@@ -479,6 +486,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_aarch64_unknown_linux_musl_binding",
     downloaded_file_path = "src_binding_release_aarch64-unknown-linux-musl.rs",
+    sha256 = "09f8900ced8297c229246c7a50b2e0ec23c54d0a554f369619cc29863f38dd1a",
     urls = [
         "https://github.com/openai/codex/releases/download/rusty-v8-v146.4.0/src_binding_release_aarch64-unknown-linux-musl.rs",
     ],
@@ -487,6 +495,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_x86_64_unknown_linux_musl_archive",
     downloaded_file_path = "librusty_v8_release_x86_64-unknown-linux-musl.a.gz",
+    sha256 = "20d8271ad712323d352c1383c36e3c4b755abc41ece35819c49c75ec7134d2f8",
     urls = [
         "https://github.com/openai/codex/releases/download/rusty-v8-v146.4.0/librusty_v8_release_x86_64-unknown-linux-musl.a.gz",
     ],
@@ -495,6 +504,7 @@ http_file(
 http_file(
     name = "rusty_v8_146_4_0_x86_64_unknown_linux_musl_binding",
     downloaded_file_path = "src_binding_release_x86_64-unknown-linux-musl.rs",
+    sha256 = "09f8900ced8297c229246c7a50b2e0ec23c54d0a554f369619cc29863f38dd1a",
     urls = [
         "https://github.com/openai/codex/releases/download/rusty-v8-v146.4.0/src_binding_release_x86_64-unknown-linux-musl.rs",
     ],