fix(torghut): add tigerbeetle stable audit refs

[gregkonush]

Summary

• Added deterministic TigerBeetle stable_ref audit payloads derived from cluster, account, source, kind, and source-signature inputs without changing existing transfer IDs.
• Persisted stable refs during TigerBeetle journaling and exposed them through runtime-ledger journal parity payloads for proof-packet/readiness consumers.
• Added a journal-script backfill pass for existing refs and reconciliation coverage/mismatch blockers for tampered stable-ref payloads.
• Preserved TigerBeetle as accounting_parity_only; payloads continue to mark promotion_authority and runtime-ledger overrides as false.

Related Issues

None

Testing

• cd services/torghut && uv sync --frozen --extra dev
• cd services/torghut && uv run --frozen pytest tests/test_tigerbeetle*.py tests/test_journal_tigerbeetle_order_events.py -q (125 passed, 1 warning)
• cd services/torghut && uv run --frozen ruff check app/trading/tigerbeetle_ids.py app/trading/tigerbeetle_journal.py app/trading/tigerbeetle_reconcile.py scripts/journal_tigerbeetle_order_events.py tests/test_tigerbeetle_ids.py tests/test_tigerbeetle_journal.py tests/test_tigerbeetle_reconcile.py tests/test_journal_tigerbeetle_order_events.py
• cd services/torghut && uv run --frozen ruff format --check app/trading/tigerbeetle_ids.py app/trading/tigerbeetle_journal.py app/trading/tigerbeetle_reconcile.py scripts/journal_tigerbeetle_order_events.py tests/test_tigerbeetle_ids.py tests/test_tigerbeetle_journal.py tests/test_tigerbeetle_reconcile.py tests/test_journal_tigerbeetle_order_events.py
• cd services/torghut && uv run --frozen pyright --project pyrightconfig.json
• cd services/torghut && uv run --frozen pyright --project pyrightconfig.alpha.json
• cd services/torghut && uv run --frozen pyright --project pyrightconfig.scripts.json
• git diff --check

Screenshots (if applicable)

N/A; backend ledger audit integration only.

Breaking Changes

None. Existing TigerBeetle transfer IDs are not rewritten; the stable-ref backfill only augments PostgreSQL ref payloads through the existing GitOps-run journal path.

Checklist

• Testing section documents the exact validation performed.
• Screenshots and Breaking Changes sections are handled appropriately.
• Documentation, release notes, and follow-ups are updated or tracked; no separate docs were required for this focused Torghut ledger audit tranche.