gfql/cypher: OR/XOR-around-pattern lowering via Apply/SemiApply runtime (#1031 slice 4)

[lmeyerov]

Parent: #1031
Depends on: #1235 foundation

This issue tracks #1031 slice 4: boolean OR/XOR expressions around pattern predicates.

Scope

• Support shapes like pattern OR row_expr and pattern XOR row_expr
• Reuse apply/semi-apply runtime foundations from slice 2b where possible
• Add compile and runtime tests for disjunctive compositions

Reference docs

• plans/1031-slices-2-3-4/HANDOFF.md
• plans/1031-slices-2-3-4/findings/slice-2-phase-2b-engine.md

[lmeyerov]

Dependency update: shared Apply/SemiApply foundation from #1235 landed via merged PR #1238 (commit bd420d6).

This slice-4 issue remains open under #1031 and can proceed in parallel with #1237 as capacity allows.