feat(realtime): order Postgres deliveries

[swkeever]

Summary

• feed normalized Postgres changes through the bounded per-channel FIFO worker
• attach subscription identity to queued callbacks and discard stale epochs
• close and replace the worker across subscription lifecycle transitions

This slice preserves existing delivery payloads. Row-fetch requests and the public auto-fetch option remain separate follow-up slices.

Verification

• uv run python scripts/check_openapi.py
• uv run ruff check .
• uv run ruff format --check .
• uv run mypy
• uv run pyright
• uv run pytest tests/unit -q (395 passed)
• uv run behave features/contract --dry-run --no-snippets
• uv run python -m build
• npm test --prefix tests/sdk-contract
• bash scripts/ci/run-sdk-contract-tests_test.sh

[swkeever]

@codex review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-03T16:54:04.203435Z	b6889d0	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 👍

Reviewed commit: b6889d04a6

ℹ️ About Codex in GitHub

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