test(synapse): table-driven embed expansion edge cases (cycles, missing targets)

[MarcoPorcellato]

Context

Wave 10 code study found SYNAPSE embed bugs (#65, #66). Lock behavior with parametrized tests before/after fixes.

Objectives

• A↔B page cycle does not duplicate outer literals
• Missing [[Page]] vs missing ((uuid)) — assert chosen policy consistently
• Simple A→B happy path still expands (B only case)

Files

• tests/test_synapse.py

Getting started

1. uv sync --all-extras && make all
2. See test_synapse_recursive_embed_expansion and test_expand_missing_block_embed_completes_without_hang

Definition of Done

• make all passes