refactor: replace YAML config with explicit Python defaults in search classes (#1202)

Remove per-search YAML config files (nest.yaml, mcmc.yaml, mle.yaml) and
the config machinery that loaded them (config_dict_search, config_dict_run,
config_type, _class_config, _config, setattr loop). All search parameters
are now explicit typed __init__ arguments with Python defaults on each
concrete search class (Nautilus, DynestyStatic, DynestyDynamic, Emcee,
Zeus, BFGS/LBFGS, Drawer). Test mode uses apply_test_mode() for direct
attribute mutation instead of dict manipulation.

Co-authored-by: Jammy2211 <JNightingale2211@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 3 people

autofit/config/non_linear/mcmc.yaml

@@ -1,6 +1,5 @@
 from typing import Optional, Tuple
 
-from autoconf import conf
 from autofit import exc
 from autofit.graphical import FactorApproximation
 from autofit.graphical.utils import Status
@@ -69,14 +68,6 @@ def __init__(
     def check_model(self, model):
         pass
 
-    @property
-    def config_type(self):
-        return conf.instance["non_linear"]["mock"]
-
-    @property
-    def config_dict_search(self):
-        return {}
-
     def _fit_fast(self, model, analysis):
         class Fitness:
             def __init__(self, instance_from_vector, result):