Change control cards for product versions

[ArtyomSavchenko]

Related TraceX ticket: https://app.tracex.co/workbench/tracex-ws/card/6a05cf2a6fdb770f2db24ea4

Adds the ability to attach cards as change control to product versions, on top of the
existing change-control document. Built as a general, reusable mechanism for linking any
class to cards with custom logic, then wired up for products.

General layer (reusable)

• New card.mixin.CardRelation mixin on core.class.Association (purpose, filter,
  requireLatest) — lets any class link cards with a semantic purpose and an optional
  eligibility filter, on top of the platform's generic relations.
• RelationEditor now honors the mixin: candidate cards are narrowed by the association's
  card type, the stored filter, and (unless disabled) the latest version.
• Exported filtersToQuery from view-resources to re-apply stored view filters as a query.

Products

• Class-level config UI on the product panel: pick change-control card types and author a
  per-type filter (creates purpose-marked associations).
• Change-control cards can be attached on the product version panel (generic relations) and
  in the "Create product version" dialog, restricted to the configured type + filter + latest.
• Creating a child version is gated: if change-control card types are configured, at least
  one card must be attached (mirrors the existing change-control document requirement).

[aonnikov]

Bad name and behavior choice. I suggest to use something applyToAnyVersion or matchAnyVersion which is enabled only when set to true

[aonnikov]

What is so specific about cards that we need a mixin for relations?