feat(sp6): wire 999 ingest → claim rejected state

T4 — calls apply_999_rejections inside /api/parse-999, then
publishes a claim.rejected event for each transitioned claim so
the Inbox live-tail refetches.

backend/src/cyclone/api.py

@@ -29,6 +29,7 @@ from fastapi.responses import JSONResponse, StreamingResponse
 from pydantic import ValidationError
 
 from cyclone import __version__
+from cyclone.inbox_state import apply_999_rejections
 from cyclone.parsers.exceptions import CycloneParseError
 from cyclone.parsers.models import BatchSummary, ClaimOutput, Envelope, ParseResult
 from cyclone.parsers.models_270 import (
@@ -568,6 +569,7 @@ def _ack_synthetic_source_batch_id(interchange_control_number: str) -> str:
 
 @app.post("/api/parse-999")
 async def parse_999_endpoint(
+    request: Request,
     file: UploadFile = File(...),
 ) -> Any:
     """Parse a 999 ACK file, persist a row, and return JSON.
@@ -617,6 +619,29 @@ async def parse_999_endpoint(
     # Build the raw 999 text from the parsed result (round-trip).
     raw_999_text = serialize_999(result, interchange_control_number=icn or "000000001")
 
+    # SP6 T4: move claims whose 999 set was rejected into ClaimState.REJECTED.
+    # The 999's set_control_number (AK202) is the source 837's ST02; in
+    # practice we look it up against patient_control_number because that's
+    # the field 999 ACKs cross-reference in this product.
+    from cyclone import db as _db
+    from cyclone.db import Claim
+    with _db.SessionLocal()() as session:
+        def _lookup(pcn: str):
+            return session.query(Claim).filter_by(patient_control_number=pcn).first()
+        _rejection_result = apply_999_rejections(
+            session, result, claim_lookup=_lookup,
+        )
+    if _rejection_result.matched:
+        bus = request.app.state.event_bus
+        for cid in _rejection_result.matched:
+            await bus.publish("claim.rejected", {"claim_id": cid})
+    if _rejection_result.orphans:
+        log.warning(
+            "999 had %d orphan set refs: %s",
+            len(_rejection_result.orphans),
+            _rejection_result.orphans[:5],
+        )
+
     row = store.add_ack(
         source_batch_id=synthetic_id,
         accepted_count=accepted,