Add manual Cloud Run invocation workflow

[Pigbibi]

Summary

• add a workflow_dispatch action to invoke HK/SG Cloud Run services through GitHub OIDC
• validate the target GitHub Environment and service variables before invoking
• add a shell test covering the workflow wiring

Tests

• bash tests/test_invoke_cloud_run_workflow.sh
• bash tests/test_sync_cloud_run_env_workflow.sh
• /home/ubuntu/Projects/LongBridgePlatform/.venv/bin/python -m ruff check .
• /home/ubuntu/Projects/LongBridgePlatform/.venv/bin/python -m unittest tests.test_runtime_config_support.RuntimeConfigSupportTests.test_dry_run_only_is_loaded_from_env

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Add checkout before authenticating to Google Cloud

Insert an actions/checkout step before google-github-actions/auth@v3; otherwise later gcloud commands can fail to authenticate in this workflow. The auth action’s own prerequisites require checkout first because it writes credentials into $GITHUB_WORKSPACE, and this job currently goes straight from input validation to auth, so manual invocations can fail before reaching the Cloud Run call.

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