fix(other-models): make clip_vision opt-in like controlnet

DEFAULT_ENABLED_OTHER_SUB_TYPES managed vae, upscaler, text_encoder and
clip_vision while controlnet was the sole opt-in type. That split was not
defensible on demand breadth: ControlNet is the broader category by install
base, and clip_vision is the narrower one (IPAdapter/SVD image conditioning,
usually one to three files) whose CivitAI type is retired upstream.

Keep the default set to the dependency-style assets every pipeline needs and
where "which one am I actually using" is the real problem - VAE, upscalers
and text encoders - and treat clip_vision and controlnet symmetrically as
opt-in. The feature is still unreleased, so the change needs no migration.

- Sync all five surfaces holding a default: DEFAULT_ENABLED_OTHER_SUB_TYPES,
  DEFAULT_SETTINGS, both DEFAULT_SETTINGS_BASE/createDefaultSettings lists,
  updateOtherModelsControls()'s fallback and the Jinja fallback.
- The selection is persisted per user, so only the untouched default moves;
  existing default_other_roots entries for a disabled sub_type are preserved.
- Fix the Jinja fallback using `or`, which treated an all-unchecked empty
  allow-list as "unset" and re-checked every box on render; `is none` keeps
  the empty list empty.
- Document the revised defaults and rationale in the plan.

Tests assert the new default trio, the normalize fallback, that both opt-in
types stay out of the default scan, and the auto-set iteration test now
enables clip_vision explicitly since it exercises the loop, not the default.

templates/components/modals/settings/library.html

@@ -41,7 +41,10 @@
 
         {{ sm.setting_toggle('enableOtherModels', 'enable_other_models', 'settings.folderSettings.enableOtherModels', 'settings.folderSettings.enableOtherModelsHelp') }}
 
-        {% set enabled_other_sub_types = settings.get('enabled_other_sub_types') or ['vae', 'upscaler', 'text_encoder', 'clip_vision'] %}
+        {# 'is none' (not 'or') so an empty allow-list stays empty instead of
+           falling back to the defaults and re-checking every box. #}
+        {% set enabled_other_sub_types = settings.get('enabled_other_sub_types') %}
+        {% if enabled_other_sub_types is none %}{% set enabled_other_sub_types = ['vae', 'upscaler', 'text_encoder'] %}{% endif %}
         <div class="setting-item other-subtype-toggles" id="otherSubTypeToggles">
             <div class="setting-row">
                 <div class="setting-info">