feat(gfql): support Cypher backtick identifiers

[lmeyerov]

Summary

• Fixes GFQL Cypher: no backtick identifiers, so columns with "." or "-" in the name cannot be referenced #2195 by preserving raw names in Cypher backtick identifiers across parsing, expression ASTs, binding, lowering, and rendering.
• Supports dotted names, hyphens, spaces, reserved words, labels, relationship types, aliases, map keys, and doubled-backtick escapes.
• Keeps unterminated backticks as syntax errors and preserves existing unquoted dotted-property semantics.
• Treats quoted atomic identifiers such as `y.z` as one projected alias for WHERE and ORDER BY.
• Preserves quoted expression-local bindings through rewrites and renders expression-reserved words (ANY, ALL, NONE, SINGLE) safely.

Exact head: 4c4aa4b186d95a7b133b61801261df41a86b08a5
Base: master@0c71cc4bb8281ecc1f07de8657c4ec45c737a5c1

Evidence

python -m pytest -q \
  graphistry/tests/compute/gfql/cypher/test_grammar_invariants.py \
  graphistry/tests/compute/gfql/cypher/test_differential_grammar_parity.py \
  graphistry/tests/compute/gfql/cypher/test_parser.py \
  graphistry/tests/compute/gfql/cypher/test_backtick_identifiers.py
# 258 passed, 1 skipped

python -m pytest -q graphistry/tests/compute/gfql/cypher
# 4075 passed, 935 skipped, 15 xfailed

python -m ruff check <changed files>
# All checks passed

python ./bin/ci/ci_type_hygiene_guard.py
# Type-hygiene guard OK (4446 grandfathered finding(s), no growth)

python ./bin/ci/ci_comment_density_guard.py
# Comment-encoding guard OK (1150 grandfathered finding(s), no growth)

git diff --check
# clean

Pandas E2E covers dotted properties, escaped backticks, WHERE filters, WITH aliases, ORDER BY, projection, expression-reserved aliases, and quoted comprehension locals. Paired TCK promoted cases pass. Exact-head Polars/cuDF and hosted CI/RTD validation follow this amendment.

Closes #2195.