refactor(automations): park manual trigger pending Run-now redesign

Manual-as-a-standalone-trigger conflates "user clicks Run now" with the
trigger model and forces ad-hoc input plumbing on the caller. Remove the
unreachable surface so the tree reflects reality (schedule is the only
v1 trigger).

- Unregister `manual`: drop import from triggers/__init__.py
- Delete `app/automations/triggers/manual/`
- Drop `RunService.dispatch_manual` (RunService is now read-only)
- Drop `POST /automations/{id}/run` and `RunDispatched` schema
- Keep `TriggerType.MANUAL` Python + PG enum value (reserved, documented)
  to avoid an Alembic round-trip when Run-now is redesigned

surfsense_backend/app/automations/services/run.py

@@ -1,46 +1,25 @@
-"""``RunService`` — dispatch and history of automation runs."""
+"""``RunService`` — read-only access to automation run history."""
 
 from __future__ import annotations
 
-from typing import Any
-
 from fastapi import Depends, HTTPException
 from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.automations.dispatch import DispatchError
 from app.automations.persistence.models.automation import Automation
 from app.automations.persistence.models.run import AutomationRun
-from app.automations.triggers.manual import dispatch_manual_run
 from app.db import Permission, User, get_async_session
 from app.users import current_active_user
 from app.utils.rbac import check_permission
 
 
 class RunService:
-    """Lifecycle of the ``AutomationRun`` resource."""
+    """Read-only access to ``AutomationRun`` history."""
 
     def __init__(self, *, session: AsyncSession, user: User) -> None:
         self.session = session
         self.user = user
 
-    async def dispatch_manual(
-        self,
-        *,
-        automation_id: int,
-        runtime_inputs: dict[str, Any] | None,
-    ) -> AutomationRun:
-        """Fire a manual run via the registered manual trigger."""
-        await self._authorize(automation_id, Permission.AUTOMATIONS_EXECUTE.value)
-        try:
-            return await dispatch_manual_run(
-                session=self.session,
-                automation_id=automation_id,
-                runtime_inputs=runtime_inputs,
-            )
-        except DispatchError as exc:
-            raise HTTPException(status_code=422, detail=str(exc)) from exc
-
     async def list(
         self,
         *,

surfsense_backend/app/automations/services/trigger.py

@@ -69,7 +69,7 @@ class TriggerService:
             trigger.enabled = data["enabled"]
 
         # Recompute next_fire_at when schedule timing changed or the trigger was
-        # toggled back on. Manual triggers always have NULL next_fire_at.
+        # toggled back on.
         if trigger.type == TriggerType.SCHEDULE:
             trigger.next_fire_at = _initial_next_fire(
                 trigger.type, trigger.params, trigger.enabled