feat(automations): add shared start_run dispatch helper

surfsense_backend/app/automations/dispatch/start.py

@@ -0,0 +1,54 @@
+"""Start one run for a trigger: resolve its automation, guard ``ACTIVE``, dispatch.
+
+Shared by every trigger type. A type's selector builds the runtime inputs and
+hands one trigger row here; this resolves and guards the automation, then calls
+the generic ``dispatch_run``.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.automations.persistence.enums.automation_status import AutomationStatus
+from app.automations.persistence.models.automation import Automation
+from app.automations.persistence.models.run import AutomationRun
+from app.automations.persistence.models.trigger import AutomationTrigger
+
+from .errors import DispatchError
+from .run import dispatch_run
+
+
+async def start_run(
+    *,
+    session: AsyncSession,
+    trigger: AutomationTrigger,
+    runtime_inputs: dict[str, Any] | None = None,
+) -> AutomationRun:
+    """Resolve ``trigger``'s automation, require it ``ACTIVE``, dispatch a run."""
+    automation = await _load_automation(session, trigger.automation_id)
+    if automation is None:
+        raise DispatchError(
+            f"automation {trigger.automation_id} not found for trigger {trigger.id}"
+        )
+
+    if automation.status != AutomationStatus.ACTIVE:
+        raise DispatchError(
+            f"automation {trigger.automation_id} is {automation.status.value}, not active"
+        )
+
+    return await dispatch_run(
+        session=session,
+        automation=automation,
+        trigger=trigger,
+        runtime_inputs=runtime_inputs,
+    )
+
+
+async def _load_automation(
+    session: AsyncSession, automation_id: int
+) -> Automation | None:
+    stmt = select(Automation).where(Automation.id == automation_id)
+    return (await session.execute(stmt)).scalar_one_or_none()