Add TYPES constant and .entailed_term factory to TermNote

[ronaldtse]

Summary

Adds standard DCA termNote type constants and a convenience factory method for creating entailedTerm cross-references.

Changes

• TYPES constant hash on Tbx::TermNote with standard ISO 30042:2019 DCA type values:

  • usageStatus, termType, grammaticalGender, grammaticalNumber, partOfSpeech, entailedTerm

• .entailed_term(target:, content: nil) factory method — creates a TermNote with type: "entailedTerm" and the given target (and optional content).

• 14 specs covering type constants, entailed_term creation, XML serialization, and round-trip.

Usage

# Create an entailedTerm cross-reference
note = Tbx::TermNote.entailed_term(target: "concept_3.1.1.4")
# => #<Tbx::TermNote type="entailedTerm" target="concept_3.1.1.4">

note.to_xml
# => <tbx:termNote type="entailedTerm" target="concept_3.1.1.4"/>

# With content
note = Tbx::TermNote.entailed_term(target: "c1", content: "related term")
note.to_xml
# => <tbx:termNote type="entailedTerm" target="c1">related term</tbx:termNote>

# Type constants
Tbx::TermNote::TYPES[:usage_status]  # => "usageStatus"
Tbx::TermNote::TYPES[:entailed_term] # => "entailedTerm"

Context

This unblocks glossarist-ruby TODO 04 (TBX cross-references via entailedTerm), enabling ConceptToTbxTransform to map related_concepts to <termNote type="entailedTerm" target="..."> elements.