Closes #1477.

Summary

• Route ordinary connected sequential MATCH ... MATCH ... Cypher queries through the existing connected-match join logical payload.
• Keep shortestPath/exotic, optional, variable-length, disconnected/cartesian-prefix, WHERE-bearing, and whole-row passthrough shapes on the existing deferred/general paths.
• Add compile/runtime cutover coverage proving ordinary sequential multi-MATCH bypasses _execute_compiled_query_chain_non_union().
• Update the existing cuDF sequential MATCH fixture to use the repo helper based on cudf.from_pandas, which is compatible with RAPIDS 26.02.

Validation

• python3 -m pytest -q graphistry/tests/compute/gfql/test_runtime_physical_cutover.py::test_anonymous_match_count_projection_uses_planned_route graphistry/tests/compute/gfql/test_runtime_physical_cutover.py::test_sequential_multiple_match_uses_connected_join_without_residual_chain graphistry/tests/compute/gfql/test_runtime_physical_cutover.py::test_classified_unplanned_chain_fallback_uses_chain_route graphistry/tests/compute/gfql/test_runtime_physical_cutover.py::test_unplanned_chain_fallback_requires_compile_defer_reason -> 6 passed
• python3 -m pytest -q graphistry/tests/compute/gfql/test_runtime_physical_cutover.py graphistry/tests/compute/gfql/test_logical_planner.py graphistry/tests/compute/gfql/cypher/test_lowering.py -k "not cudf" -> 989 passed, 12 skipped, 113 deselected
• ./bin/ruff.sh graphistry/compute/gfql/cypher/lowering.py graphistry/tests/compute/gfql/test_runtime_physical_cutover.py graphistry/tests/compute/gfql/cypher/test_lowering.py
• ./bin/typecheck.sh graphistry/compute/gfql/cypher/lowering.py
• DGX RAPIDS 25.02 targeted GFQL/cuDF selector -> 7 passed
• DGX RAPIDS 26.02 targeted GFQL/cuDF selector -> 7 passed
• python3 bin/ci_cypher_surface_guard.py after intentional baseline update for the new compiler route -> pass
• Review skill converged after 2 waves; no blocker/important findings.

Residual Scope

• Local literal-query scanner reduced multiple_match_stages from 37 to 35 on the original Harden residual Cypher unplanned-chain fallback #1476 audit baseline.
• Remaining cases are intentionally left deferred/split candidates, dominated by shortestPath/exotic and non-ordinary sequential shapes.