[P3][icebox] MultiSelectField: support per-option `visibleWhen` cascading (parity with single SelectField)

[os-zhuang]

Context

#2709 made a select field/param declared multiple: true render the multi-value chip picker (MultiSelectField) by delegating inside SelectField. That fixed the real bug (multiple values were unstorable in the single-value dropdown).

Known gap: the chip picker does not implement the per-option visibleWhen CEL cascading / dependsOn gating that single SelectField has (ADR-0058). So a multi-select whose options depend on a sibling field or the current user would show the unfiltered option set. Single selects are unaffected.

Why this is icebox (not urgent)

Multi-select combined with per-option cascading is not a combination in use today — and the pre-#2709 behavior was strictly worse (a multi-value field that couldn't hold multiple values at all). This is a completeness follow-up, to be picked up only when a real multi-select-with-dependent-options need appears.

Scope (when actioned)

• Share the option-resolution logic (resolveVisibleOptions / isOptionGroupGated / resolveDependsOnFields from @object-ui/core) between SelectField and MultiSelectField (extract a small hook/util rather than duplicating).
• MultiSelectField applies visibleWhen filtering + dependsOn gating (empty/gated hint) like single select.
• Cascade-clear: drop selected values no longer offered when the parent changes.
• Tests mirroring SelectField.cascade.test.tsx for the multi case.

Acceptance

• A multiple select with dependsOn + per-option visibleWhen narrows its offered chips identically to the single select, and clears now-invalid selections.

Refs

• feat(fields): select+multiple → multi-value chip picker; restore fields/core lint gates #2709 (the delegation that introduced this gap) · ADR-0058 (cascading & role-gated select options) · SelectField.cascade.test.tsx