refactor: future-annotations headers keep aggregator annotations lazy (PyAutoFit#1505)

Three aggregator modules evaluated af.Aggregator/af.GridSearchAggregator in
def-time annotations, re-triggering the sqlalchemy/database import the
import-time task defers.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: 2 people

autolens/aggregator/fit_imaging.py

@@ -14,6 +14,8 @@
   that exposes a generator of ``FitImaging`` objects, enabling memory-efficient iteration
   over large result sets.
 """
+
+from __future__ import annotations
 from typing import Optional, List
 
 import autofit as af

autolens/aggregator/fit_interferometer.py

@@ -15,6 +15,8 @@
   ``Aggregator`` that exposes a generator of ``FitInterferometer`` objects, enabling
   memory-efficient iteration over large result sets.
 """
+
+from __future__ import annotations
 from typing import Optional, List
 
 import autofit as af

autolens/aggregator/subhalo.py

@@ -10,6 +10,8 @@
 for the best-fit model in each cell — both the "with subhalo" fit and (optionally) the
 "no subhalo" baseline — enabling the per-cell log-evidence difference map to be computed.
 """
+
+from __future__ import annotations
 from typing import Optional
 
 import autofit as af