HEL-176: 公司端转账往来明细筛选与导出

新增 events 组合筛选 + keyset 分页，以及仅导出已确认明细的 CSV（含审计）；
与 B-44 ledger /events 按查询参数分发，不改库表与确认语义。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

server.py

@@ -155,10 +155,13 @@ class AppHandler(SimpleHTTPRequestHandler):
             self._handle_admin_intercompany_evidence(int(admin_evidence.group(1)))
             return
 
-        # Company transfer-summary (HEL-169/HEL-175, eligible_intercompany_events)
+        # Company transfer-summary (HEL-169/HEL-175/HEL-176)
         if path == "/api/company/intercompany/summary":
             self._handle_company_intercompany_summary(query)
             return
+        if path == "/api/company/intercompany/export.csv":
+            self._handle_company_intercompany_export_csv(query)
+            return
 
         # B-44 intercompany positions (company, own-company scope)
         if path == "/api/company/intercompany/balances":
@@ -169,7 +172,12 @@ class AppHandler(SimpleHTTPRequestHandler):
             self._handle_company_intercompany_pair(int(company_pair.group(1)), query)
             return
         if path == "/api/company/intercompany/events":
-            self._handle_company_intercompany_events(query)
+            # HEL-176 transfer-detail list shares this path with B-44 ledger
+            # events; dispatch by distinctive query params (to/direction/…).
+            if company_transfers.is_transfer_summary_events_query(query):
+                self._handle_company_transfer_summary_events(query)
+            else:
+                self._handle_company_intercompany_events(query)
             return
         if path == "/api/company/manual-records":
             self._handle_company_manual_records(query)
@@ -2889,6 +2897,111 @@ class AppHandler(SimpleHTTPRequestHandler):
         finally:
             connection.close()
 
+    def _reject_forged_company_id(self, query: dict[str, list[str]]) -> bool:
+        """Return True when the handler already sent a 400 for company_id."""
+        if (query.get("company_id") or [None])[0] is not None:
+            self._send_json(
+                400,
+                {"status": "error", "message": "不允许传入 company_id 参数。"},
+            )
+            return True
+        return False
+
+    def _handle_company_transfer_summary_events(
+        self, query: dict[str, list[str]]
+    ) -> None:
+        """HEL-176 filtered transfer-detail list (keyset pagination)."""
+        connection = connect(DB_PATH)
+        try:
+            user, company_id = self._company_intercompany_scope(connection)
+            if company_id is None:
+                return
+            if self._reject_forged_company_id(query):
+                return
+            try:
+                payload = company_transfers.company_intercompany_events(
+                    connection,
+                    company_id=int(company_id),
+                    from_=(query.get("from") or [None])[0],
+                    to=(query.get("to") or [None])[0],
+                    counterparty_id=(query.get("counterparty_id") or [None])[0],
+                    direction=(query.get("direction") or [None])[0],
+                    state=(query.get("state") or [None])[0],
+                    limit=(query.get("limit") or [None])[0],
+                    cursor=(query.get("cursor") or [None])[0],
+                )
+            except company_transfers.TransferSummaryInputError as exc:
+                self._send_json(400, {"status": "error", "message": str(exc)})
+                return
+            self._send_json(200, {"status": "ok", **payload})
+        finally:
+            connection.close()
+
+    def _handle_company_intercompany_export_csv(
+        self, query: dict[str, list[str]]
+    ) -> None:
+        """Confirmed-only CSV export; session company scope + audit (HEL-176)."""
+        connection = connect(DB_PATH)
+        try:
+            user, company_id = self._company_intercompany_scope(connection)
+            if company_id is None:
+                return
+            if self._reject_forged_company_id(query):
+                return
+            # Pending must never leave via export, even if a client sends state=.
+            if (query.get("state") or [None])[0] not in (None, "", "confirmed"):
+                self._send_json(
+                    400,
+                    {
+                        "status": "error",
+                        "message": "导出仅支持已确认明细，不允许导出待确认。",
+                    },
+                )
+                return
+            try:
+                items, meta = company_transfers.company_intercompany_export_rows(
+                    connection,
+                    company_id=int(company_id),
+                    from_=(query.get("from") or [None])[0],
+                    to=(query.get("to") or [None])[0],
+                    counterparty_id=(query.get("counterparty_id") or [None])[0],
+                    direction=(query.get("direction") or [None])[0],
+                )
+            except company_transfers.TransferSummaryInputError as exc:
+                self._send_json(400, {"status": "error", "message": str(exc)})
+                return
+            content = company_transfers.render_intercompany_export_csv(items)
+            detail_parts = [
+                f"rows:{meta['row_count']}",
+                f"from:{meta['start']}",
+                f"to:{meta['end']}",
+                "state:confirmed",
+            ]
+            if meta["counterparty_id"] is not None:
+                detail_parts.append(f"counterparty_id:{meta['counterparty_id']}")
+            if meta["direction"] is not None:
+                detail_parts.append(f"direction:{meta['direction']}")
+            auth.audit(
+                connection,
+                "export_intercompany_csv",
+                actor=user,
+                target=f"company:{company_id}",
+                detail=";".join(detail_parts),
+                ip=self._client_ip,
+            )
+            self.send_response(200)
+            self.send_header("Content-Type", "text/csv; charset=utf-8")
+            self.send_header(
+                "Content-Disposition",
+                'attachment; filename="intercompany-export.csv"',
+            )
+            self.send_header("Content-Length", str(len(content)))
+            self.send_header("Cache-Control", "no-store")
+            self.end_headers()
+            self.wfile.write(content)
+        finally:
+            connection.close()
+
     def _handle_company_intercompany_balances(self, query: dict[str, list[str]]) -> None:
         connection = connect(DB_PATH)
         try: