refactor: add agent_id to various interfaces and improve field organization

backend/migrations/versions/b7a1d9c3e4f5_add_agent_id_to_board_webhooks.py

@@ -0,0 +1,38 @@
+"""Add optional agent mapping to board webhooks.
+
+Revision ID: b7a1d9c3e4f5
+Revises: a2f6c9d4b7e8
+Create Date: 2026-02-15 14:00:00.000000
+"""
+
+from __future__ import annotations
+
+import sqlalchemy as sa
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision = "b7a1d9c3e4f5"
+down_revision = "a2f6c9d4b7e8"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """Add optional mapped agent reference on board webhooks."""
+    op.add_column("board_webhooks", sa.Column("agent_id", sa.Uuid(), nullable=True))
+    op.create_index("ix_board_webhooks_agent_id", "board_webhooks", ["agent_id"], unique=False)
+    op.create_foreign_key(
+        "fk_board_webhooks_agent_id_agents",
+        "board_webhooks",
+        "agents",
+        ["agent_id"],
+        ["id"],
+    )
+
+
+def downgrade() -> None:
+    """Remove optional mapped agent reference from board webhooks."""
+    op.drop_constraint("fk_board_webhooks_agent_id_agents", "board_webhooks", type_="foreignkey")
+    op.drop_index("ix_board_webhooks_agent_id", table_name="board_webhooks")
+    op.drop_column("board_webhooks", "agent_id")