Function ValidateMaterializationTargets

Validates materialization targets for a DataFeatureSpec against loaded metadata. Performs deep schema contract validation:

• Target column exists, is not virtual
• Numeric constraint bounds fit within column precision/scale (e.g. DECIMAL(5,4) max is 9.9999)
• String/text constraints fit within column Length
• Enum constraints agree with column CHECK constraint value list
• Foreign key targets resolve to existing related entities and valid non-virtual match fields
• Child targets resolve to existing entities with type-compatible ParentField and valid mapped fields
• Tag targets have valid UUID RootTagID, valid MaxDepth, valid Growth, and valid MatchThreshold