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.

py/utils/constants.py

@@ -97,11 +97,17 @@ VALID_OTHER_SUB_TYPES = ["vae", "upscaler", "text_encoder", "clip_vision", "cont
 # Sub-types managed when the (opt-in) Other Models feature is switched on.
 # The feature itself defaults to off (``enable_other_models`` = False), so
 # nothing here is scanned until the user enables it.
+#
+# The default set is deliberately limited 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. ``clip_vision`` and ``controlnet`` are
+# workflow-driven instead (IPAdapter/SVD, per-workflow ControlNet variants) and
+# ControlNet libraries routinely run to dozens of files, so both stay opt-in
+# and are treated symmetrically.
 DEFAULT_ENABLED_OTHER_SUB_TYPES: List[str] = [
     "vae",
     "upscaler",
     "text_encoder",
-    "clip_vision",
 ]