[BUG] PR 侧边栏将从未发送的检查套件视为"正在进行"

Describe the bug

The PR sidebar's checks section reports checks as in progress when none are running. On a PR of mine, it shows 4 skipped, 4 in progress while GitHub's own PR page shows only the 4 skipped checks and nothing pending. The Pending list in the sidebar also gets 4 entries labelled Workflow.

The cause is the check suites loop at the end of getChecksStats (internal/tui/components/prview/checks.go:646):

// Count check suites that don't appear in statusCheckRollup
for _, suite := range lastCommit.Commit.CheckSuites.Nodes {
	if suite.Conclusion == "ACTION_REQUIRED" {
		res.awaitingApproval++
	} else if suite.Status == "QUEUED" || suite.Status == "PENDING" || suite.Status == "WAITING" {
		res.inProgress++
	}
}

GitHub returns check suites that were created but never dispatched: status: QUEUED, conclusion: null, workflowRun: null, and zero check runs. They are invisible in GitHub's UI, but every one of them bumps inProgress here. The same loop at checks.go:446 renders them in the Pending section, falling back to the "Workflow" placeholder name because neither the workflow nor the app name is set.