Deprecation mechanism for metamodel yaml

[a-zw]

What

Add support for deprecated_options and deprecated_links in the metamodel.
These are not validated (no regex, no type checking).
They only emit INFO-level messages when a need still uses them, so they don't break builds
but alert users to migrate.

Example YAML syntax:

feat_req:
  title: Feature Requirement
  mandatory_options:
    status: ^(valid|invalid)$
  optional_links:
    derived_from: stkh_req
    belongs_to: feat
  deprecated_links:
    satisfies: use derived_from instead

Acceptance Criteria (DoD)

tbd

How

tbd