refactor(automations): move schedule trigger into builtin package

surfsense_backend/app/automations/triggers/builtin/schedule/params.py

@@ -0,0 +1,24 @@
+"""``ScheduleTriggerParams`` — params for the ``schedule`` trigger type."""
+
+from __future__ import annotations
+
+from pydantic import BaseModel, ConfigDict, Field, model_validator
+
+from .cron import InvalidCronError, validate_cron
+
+
+class ScheduleTriggerParams(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    cron: str = Field(
+        ..., description="Five-field cron expression.", examples=["0 9 * * 1-5"]
+    )
+    timezone: str = Field(..., description="IANA timezone.", examples=["Africa/Kigali"])
+
+    @model_validator(mode="after")
+    def _validate(self) -> ScheduleTriggerParams:
+        try:
+            validate_cron(self.cron, self.timezone)
+        except InvalidCronError as exc:
+            raise ValueError(str(exc)) from exc
+        return self