[codex] Add comprehensive root formatting check (#25683)

## Why

The root formatting entrypoints could drift: `just fmt` did not format
the Justfile itself, and the CI-facing check recipe only checked Python
scripts instead of matching everything formatted by `just fmt`.

## What changed

- Add a shared cross-platform Python formatter driver used by both `just
fmt` and `just fmt-check`.
- Run Justfile, Rust, Python SDK, and internal-script formatter groups
concurrently while buffering each formatter group's output until it
finishes.
- Log formatter starts immediately, then print each formatter group's
labeled output when it completes.
- Keep the SDK lint-fix and Ruff formatting passes ordered, with source
comments explaining their distinct roles and the check-mode equivalents.
- Run Ruff through shared `uv run --no-sync --with ruff` overlays so
formatting works on clean glibc Linux checkouts without installing the
platform-specific SDK runtime wheel.
- Show `fmt-check` help text in `just -l` and simplify CI to call the
shared driver through `just fmt-check`.
- Pin the general CI workflow to `just@1.51.0` so its formatter agrees
with the checked-in Justfile.
- Add regression coverage for the thin Just recipes and the driver's
formatter graph.

## Validation

- `just fmt`
- `just fmt-check`
- `python3 -m pytest
sdk/python/tests/test_artifact_workflow_and_binaries.py -k 'root_fmt or
root_format' -q`
- `pnpm run format`
- `git diff --check`
- `just -l | rg -n '^    fmt|fmt-check'`
- `uvx --from uv==0.7.22 uv run --frozen --project sdk/python --no-sync
--with ruff ruff check --diff sdk/python`

.github/workflows/ci.yml

@@ -76,13 +76,13 @@ jobs:
 
       - uses: taiki-e/install-action@44c6d64aa62cd779e873306675c7a58e86d6d532 # v2.62.49
         with:
-          tool: just
+          tool: just@1.51.0
       - name: Install uv
         uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
         with:
           version: "0.11.3"
-      - name: Ruff format Python scripts (run `just fmt` to fix)
-        run: just fmt-scripts-check
+      - name: Check formatting (run `just fmt` to fix)
+        run: just fmt-check
 
       - name: Prettier (run `pnpm run format:fix` to fix)
         run: pnpm run format