feat(glossaries): add target_language support - DB migration, API, and UI language pair display

database/models.py

@@ -331,6 +331,7 @@ class Glossary(Base):
     )
     name = Column(String(255), nullable=False)
     source_language = Column(String(10), nullable=False, default="fr")
+    target_language = Column(String(10), nullable=True, default="en")
     created_at = Column(DateTime, default=_utcnow)
     updated_at = Column(DateTime, default=_utcnow, onupdate=_utcnow)
 
@@ -348,6 +349,7 @@ class Glossary(Base):
             "user_id": self.user_id,
             "name": self.name,
             "source_language": self.source_language,
+            "target_language": self.target_language,
             "terms": [term.to_dict() for term in self.terms] if self.terms else [],
             "created_at": self.created_at.isoformat() if self.created_at else None,
             "updated_at": self.updated_at.isoformat() if self.updated_at else None,