Add shared execution outcome notifications

[Pigbibi]

Summary

• add shared execution outcome/stage helpers for platform runtimes
• add shared notification envelope and publisher helpers
• document that platform repos should keep broker differences behind adapters and transport wiring

Tests

• .venv/bin/python -m pytest -q

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 1d9bd5d2f1

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Include dry-run and no-action in terminal stage set

resolve_strategy_run_stage can return DRY_RUN_COMPLETED (when dry_run_only=True) and NO_ACTION (when nothing is executed), but DEFAULT_TERMINAL_STRATEGY_RUN_STAGES excludes both values. Any caller that uses is_terminal_strategy_run_stage with the default set will misclassify these finished runs as non-terminal, which can keep polling/retry loops alive for dry-run and no-op executions. The terminal set should include these returned terminal outcomes (or the resolver should stop emitting them).

Useful? React with 👍 / 👎.