test(cypher): add IC10-shaped bound-alias NOT-pattern regression

[lmeyerov]

Summary

• add bound-alias NOT-pattern lowering/runtime regression coverage for issue gfql/cypher: bound-aliases NOT-pattern + IC10 unblock (#1031 slice 2 phase 2c) #1237
• add an IC10-shaped direct Cypher regression:
  • MATCH (root {id: 'a'})-[:R]->(mid)-[:R]->(cand) WHERE NOT (root)-[:R]->(cand) RETURN cand.id AS cand_id ORDER BY cand_id
• keep existing bound-alias and mixed row+NOT coverage in graphistry/tests/compute/gfql/cypher/test_lowering.py
• update CHANGELOG.md (Development → Tests) with the new gfql/cypher: bound-aliases NOT-pattern + IC10 unblock (#1031 slice 2 phase 2c) #1237 IC10-shaped regression coverage note

Validation

• -k "ic10_shaped_bound_alias_negated_pattern or bound_alias_negated_pattern or negated_pattern_where_predicate" → passed
• -k "negated_pattern_where_predicate or bound_alias_negated_pattern or where_not_pattern_on_optional_match or ic10_shaped_bound_alias_negated_pattern" → passed

Refs #1237