fix(api): set compatibility options without crashing

clip_skip and the uni_pc_* opts live in opts.data without an OptionInfo in
data_labels (compatibility_opts). Options.set() read data_labels[key].onchange
unconditionally, so setting clip_skip via /sdapi/v1/options raised KeyError and
returned 500; the override_settings restore path had the same unguarded
data_labels[k] access for falsy-valued compat opts.

Guard the onchange lookup and read the stored value via getattr(opts, k), which
already falls back through data then data_labels.

modules/options_handler.py

@@ -109,7 +109,8 @@ class Options:
             setattr(self, key, value)
         except RuntimeError:
             return False
-        func = self.data_labels[key].onchange
+        # compatibility_opts (e.g. clip_skip) live in data without a data_labels entry
+        func = self.data_labels[key].onchange if key in self.data_labels else None
         if func is not None:
             try:
                 func()

modules/processing.py

@@ -153,11 +153,12 @@ def process_images(p: StableDiffusionProcessing) -> Processed | None:
     for k, v in p.override_settings.copy().items():
         if shared.opts.data.get(k, None) is None and shared.opts.data_labels.get(k, None) is None:
             continue
-        orig = shared.opts.data.get(k, None) or shared.opts.data_labels[k].default
+        # getattr resolves the value via data then data_labels; compat opts (clip_skip) have no data_labels entry
+        orig = getattr(shared.opts, k, None)
         if orig == v or (type(orig) == str and os.path.splitext(orig)[0] == v):
             p.override_settings.pop(k, None)
     for k in p.override_settings.keys():
-        stored_opts[k] = shared.opts.data.get(k, None) or shared.opts.data_labels[k].default
+        stored_opts[k] = getattr(shared.opts, k, None)
     results = None
     try:
         # if no checkpoint override or the override checkpoint can't be found, remove override entry and load opts checkpoint