#1273: Admit shape A WITH multi-alias scalar projection + convert tests

[lmeyerov]

Summary

• admit Cypher/GFQL: admit multi-MATCH-source row projection without hidden carries (IC5 sub-residual B) #1273 shape A (MATCH ... WITH a.id, b.id RETURN ...) by enabling first-stage bindings-row lowering for multi-alias non-aggregate WITH scalar projections
• keep Cypher/GFQL: admit multi-MATCH-source row projection without hidden carries (IC5 sub-residual B) #1273 shapes B/C/D rejected and explicit to Cypher/GFQL: admit multi-MATCH-source row projection without hidden carries (IC5 sub-residual B) #1273
• convert shape-A rejection test to positive execution assertion
• update adjacent now-executing carry-shape tests to positive assertions
• adjust one aggregate-overlap case to assert its primary non-Cypher/GFQL: admit multi-MATCH-source row projection without hidden carries (IC5 sub-residual B) #1273 aggregate-expression error

Validation

• python -m pytest -q graphistry/tests/compute/gfql/cypher/test_lowering.py -k "multi_alias_with_stage_scalar_projection_executes or unsound_multi_source_aggregate_overlap or unwind_reentry_progresses_past_parser_to_row_scope_boundary or post_with_match_collect_unwind_match_final_with_carried_scalar or post_with_match_collect_unwind_match_final_with_order_by_limit"
• uv run ruff check graphistry/compute/gfql/cypher/lowering.py graphistry/tests/compute/gfql/cypher/test_lowering.py

Closes #1273