[Bug]: cargo metadata compatibility warning repeated in every CI metadata validation step

[1688mengdie]

Summary

The upstream CI logs for main show a cargo toolchain warning repeated in every "Verify ... metadata" step. Evidence from GitHub Actions run 33035362609 (also present in runs 33050974141, 33047041028, and the latest snapshot run 33057289117):

warning: please specify `--format-version` flag explicitly to avoid compatibility problems

It is emitted by the three cargo metadata --locked --no-deps invocations in .github/workflows/ci.yml (the "Verify committed Cargo metadata", "Verify committed release metadata", and "Verify projected release metadata" steps). It appears once per runner in the Rust Build Check jobs and again in the frontend job, i.e. it pollutes every CI run of main.

Root Cause Analysis

• Newer cargo releases print this compatibility warning whenever cargo metadata is invoked without an explicit --format-version flag. The workflow calls omit the flag, so every run produces the warning even though the invocation itself succeeds.
• This is a CI-configuration-layer issue, not a code warning: no source change is involved.

Proposed Fix

Add --format-version 1 explicitly to the three cargo metadata --locked --no-deps invocations in .github/workflows/ci.yml, so:

• the compatibility warning disappears from the CI logs;
• the invocation pins its machine-readable output contract explicitly, protecting against future cargo default changes.

No workflow semantics change: the same metadata is validated with the same lockfile, just with the format version made explicit.