feat: add board webhook configuration and payload models

backend/app/models/board_webhook_payloads.py

@@ -0,0 +1,32 @@
+"""Persisted webhook payloads received for board webhooks."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID, uuid4
+
+from sqlalchemy import JSON, Column
+from sqlmodel import Field
+
+from app.core.time import utcnow
+from app.models.base import QueryModel
+
+RUNTIME_ANNOTATION_TYPES = (datetime,)
+
+
+class BoardWebhookPayload(QueryModel, table=True):
+    """Captured inbound webhook payload with request metadata."""
+
+    __tablename__ = "board_webhook_payloads"  # pyright: ignore[reportAssignmentType]
+
+    id: UUID = Field(default_factory=uuid4, primary_key=True)
+    board_id: UUID = Field(foreign_key="boards.id", index=True)
+    webhook_id: UUID = Field(foreign_key="board_webhooks.id", index=True)
+    payload: dict[str, object] | list[object] | str | int | float | bool | None = Field(
+        default=None,
+        sa_column=Column(JSON),
+    )
+    headers: dict[str, str] | None = Field(default=None, sa_column=Column(JSON))
+    source_ip: str | None = None
+    content_type: str | None = None
+    received_at: datetime = Field(default_factory=utcnow, index=True)