fix: auto-stage-candidate active dispatch (replaces broken workflow_run trigger)

[bash0816]

概要

auto-stage-candidate.ymlのworkflow_runトリガーが2026-07-08以降GitHub Actions側の配信不具合で一度も発火していないことが判明したため、能動的なworkflow_dispatch呼び出しに置き換えました。

変更内容

• auto-stage-candidate.yml: workflow_runトリガーを削除し、workflow_dispatch入力(build_run_id)に置き換え
• external-build-android-aarch64.yml: ビルド完了時にauto-stage-candidateをactiveに呼び出すジョブを追加

レビュー状況

G1(設計レビュー: 5回)・G2(実装プランレビュー: 4回)のGPT-5.6-terraレビューで全てGoを取得済み。現在G3コーディングレビュー待ち。

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Dispatch staging only after the build run completes

When this job dispatches auto-stage-candidate, the source workflow run is still in progress because dispatch-stage itself has not finished yet. The dispatched workflow immediately queries this same ${{ github.run_id }} and requires status=completed and conclusion=success, so the actively dispatched run will see in_progress/null and exit before staging; successful builds therefore won't auto-stage unless someone dispatches the workflow manually after the build workflow has completed.

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