ci(gfql/polars): run cypher test_lowering polars cases in the polars lane

The polars-parametrized cypher tests (numeric fns, toLower, =~ parity in
graphistry/tests/compute/gfql/cypher/test_lowering.py) never executed in CI:
the core lane has no polars installed (importorskip -> skip) and the polars
lane's fixed file list excluded the file. So the polars numeric lowerings this
branch adds were CI-untested and their changed lines uncovered (coverage gate
76.9% < 80). Add the file (-k polars) to bin/test-polars.sh and the ci.yml
polars coverage step (--cov-append). Moved from the stacked #1677 to here — it
belongs with the lowerings it tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: lmeyerov

.github/workflows/ci.yml

@@ -1413,6 +1413,9 @@ jobs:
           graphistry/tests/compute/gfql/test_engine_polars_chain.py \
           graphistry/tests/compute/gfql/test_engine_polars_row_pipeline.py \
           graphistry/tests/compute/gfql/test_engine_polars_cypher_conformance.py
+        COVERAGE_FILE=build/polars-coverage/coverage.polars-py3.12 python -B -m pytest -vv \
+          --cov=graphistry/compute --cov-report= --cov-append \
+          graphistry/tests/compute/gfql/cypher/test_lowering.py -k polars
 
     - name: Upload polars coverage
       if: ${{ matrix.python-version == '3.12' }}

bin/test-polars.sh

@@ -15,3 +15,7 @@ python -B -m pytest -vv \
     graphistry/tests/compute/gfql/test_engine_polars_chain.py \
     graphistry/tests/compute/gfql/test_engine_polars_row_pipeline.py \
     graphistry/tests/compute/gfql/test_engine_polars_cypher_conformance.py
+
+# cypher-lowering polars-parametrized cases (round ties, lower/upper, =~, numeric fns)
+python -B -m pytest -vv \
+    graphistry/tests/compute/gfql/cypher/test_lowering.py -k polars