Added dynamic model crosswalk associations - fixes #1399

[philayres]

Summary

• Support dynamic models associated to masters through msid, pro_id, pro_info_id, and contact_id.
• Keep the dynamic model primary key independent from the masters-side join key.
• Preserve deliberately configured foreign keys when existing tables also contain master_id.
• Validate foreign-key column compatibility using Rails-normalized types, accepting equivalent integer and string database types.
• Update scoping and admin documentation and add model/view regression coverage.

Validation

• bundle exec rspec spec/models/definition_scoping_spec.rb spec/views/masters/_dynamic_model_blocks_crosswalk_spec.rb
• Result: 23 examples, 0 failures.
• Coverage includes compatible integer/bigint variants and rejection of incompatible foreign-key types for crosswalk and external-ID associations.
• git diff --check

Fixes #1399