feat(s52): MAF-free nested payload builder (verdict_to_dict oracle) + file notifier

src/portfolio_optimiser/notify.py

@@ -15,8 +15,10 @@ Registered in ``tests/test_okf.py``'s ``_MAF_FREE_MODULES`` (direct-import guard
 
 from __future__ import annotations
 
+import json
 import sys
-from typing import TYPE_CHECKING, Protocol, TextIO, runtime_checkable
+from pathlib import Path
+from typing import TYPE_CHECKING, Any, Protocol, TextIO, runtime_checkable
 
 if TYPE_CHECKING:  # verdicts imports agent_framework — keep it out of the runtime import graph
     from portfolio_optimiser.verdicts import Verdict
@@ -46,3 +48,35 @@ class ConsoleNotifier:
 
     def __call__(self, verdict: Verdict) -> None:
         print(f"[notify] verdict {verdict.id} decision={verdict.decision}", file=self._stream)
+
+
+def _verdict_payload(verdict: Verdict) -> dict[str, Any]:
+    """NESTED, byte-deterministic, duck-typed payload — reproduces ``verdicts.verdict_to_dict``'s
+    exact shape (verdicts.py:124-139) WITHOUT importing it (a runtime import would pull
+    ``agent_framework``). Pinned against drift by the ``== verdict_to_dict(v)`` oracle test."""
+    f = verdict.proposal_features
+    return {
+        "id": verdict.id,
+        "decision": verdict.decision,
+        "rationale": verdict.rationale,
+        "proposal_features": {
+            "affected_codes": sorted(f.affected_codes),
+            "measure_type": f.measure_type,
+            "claimed_saving_nok": f.claimed_saving_nok,
+            "description": f.description,
+        },
+    }
+
+
+class FileNotifier:
+    """Appends one JSONL line per verdict (byte-deterministic: ``sort_keys`` + LF, no wall-clock —
+    the ``outbox._dump`` idiom). Parent directories are created as needed."""
+
+    def __init__(self, path: str) -> None:
+        self._path = Path(path)
+
+    def __call__(self, verdict: Verdict) -> None:
+        self._path.parent.mkdir(parents=True, exist_ok=True)
+        line = json.dumps(_verdict_payload(verdict), sort_keys=True) + "\n"
+        with self._path.open("a", encoding="utf-8") as handle:
+            handle.write(line)