[Bug]: ARM64 SCA self-hosted runner loses communication during analysis

### Is there an existing issue for the same bug?

- [x] I searched open and closed MatrixOne issues for the exact runner-communication annotation, SCA arm64 runner disconnects, and the affected runner label. No matching issue was found. #27127 tracks a different failure: an outbound GitHub API TLS disconnect confined to `pr-size-label`.

### Branch Name

main (observed on PR #27733 against main)

### Commit ID

- PR head: `3b9ff2e159f2c17dea23dd6b276eb16023b8b317`
- PR base: `b0ae66c04d9a67175d2dfb8bf1c777fb888e1430`

### Other Environment Information

- Workflow: MatrixOne ALL CI
- Run: https://github.com/matrixorigin/matrixone/actions/runs/33046076856 (attempt 1)
- Failed job: https://github.com/matrixorigin/matrixone/actions/runs/33046076856/job/98430301949
- Job: Matrixone CI / SCA Test on Linux/arm64
- Runner label: `arm64-mo-shanghai-4c8g`
- Runner: `arm64-mo-shanghai-4c8g-jj2z7-runner-xsmx4`
- Failed phase: Static Code Analysis

### Actual Behavior

The arm64 SCA job lost its self-hosted runner during Static Code Analysis. The check run contains one failure annotation and no source-code analysis diagnostic:

```text
The self-hosted runner lost communication with the server. Verify the machine is running and has a healthy network connection. Anything in your workflow that terminates the runner process, starves it for CPU/Memory, or blocks its network access can cause this error.
```

The job ran from `2026-08-27T06:30:21Z` to `2026-08-27T07:15:39Z`; Static Code Analysis began at `2026-08-27T06:38:01Z`. The check-run annotation points to `.github`, not a MatrixOne source file.

### Expected Behavior

The self-hosted arm64 runner should remain connected until SCA completes, and the job should report an actionable SCA diagnostic if analysis itself fails.

### Steps to Reproduce

1. Trigger MatrixOne ALL CI for PR #27733 at head `3b9ff2e159f2c17dea23dd6b276eb16023b8b317`.
2. Schedule `Matrixone CI / SCA Test on Linux/arm64` on runner `arm64-mo-shanghai-4c8g-jj2z7-runner-xsmx4`.
3. Let the job enter `Static Code Analysis`.
4. Observe job 98430301949 fail with the self-hosted-runner communication annotation and no SCA finding.

### Additional information

This failure is unrelated to PR #27733:

- the PR changes only `pkg/frontend/snapshot.go` and `pkg/tests/issues/issue_27718_test.go`;
- it does not modify GitHub Actions, runner configuration, SCA configuration, or infrastructure;
- the shared build, UT coverage, Proxy BVT, and Pessimistic BVT checks for the exact PR head succeeded;
- the check-run API reports only runner communication loss, with no compiler, test, lint, or static-analysis failure.

The workflow run was still completing an independent UT job when the failed-job log endpoint was queried, but the check-run annotation is terminal and directly identifies the infrastructure failure. Per CI handling policy, the failed jobs of attempt 1 will be rerun exactly once after this occurrence is recorded.