A.19.SOURCE-SET-SPACE-SUBSTRATE:4.11 - Ordinary and heavier use

For ordinary use, one short declaration block is enough:

• one SourceSetFamily;
• SourceSetRef? when family-level naming alone would be ambiguous;
• one SearchSpaceRef;
• one OutcomeSpaceRef;
• one explicit SpaceRefRelationKind;
• one explicit relation line;
• one explicit posture line.

Use the heavier stack only when one of these is true:

• several declared source sets are genuinely composed;
• one derived view must stay recoverable;
• one interpretive qualifier is materially active;
• one descriptor-map or distance-definition docking clause is needed to prevent collapse;
• or the reader would otherwise mistake publication metadata for substrate semantics.