Keep the PostgreSQL JSON-path operator intact

[jadenfix]

@? is split into @ and a ? placeholder, so formatting SELECT data@?? with use_space_around_operators=True produces SELECT data @ ??. Recognize the PostgreSQL JSON-path operator as one token, preserving the following parameter: SELECT data @? ?.

Related to the JSON operator documentation linked in #613. This only fixes @?; it does not resolve that whole issue. ?| and ?& remain outside this change because they are ambiguous with a ? parameter followed by a bitwise operator. Added parsing and formatting regressions plus controls for parameters followed by ||, | and &.

Validation: make test passes on Python 3.10–3.14 (512 passed, 2 expected failures and 1 existing unexpected pass per version); lint, coverage (97%), and package build pass. The full native test matrix also passes on the exact PR commit: Python 3.10–3.14 on Linux and Python 3.11 on macOS and Windows. Confirmed @? tokenization and formatting fail on the base commit and pass with this change, while parameter/operator controls retain their original behavior.

• ran the tests (pytest)
• all style issues addressed (ruff)
• changes are covered by tests
• documentation reviewed; no public API change

Required upstream checks still await maintainer approval.

Prepared with OpenAI Codex assistance.

[jadenfix]

@andialbrecht, could you approve the pending fork CI and take a look when convenient? This now only fixes the PostgreSQL JSON-path operator @?. On review I narrowed the change to preserve ? parameters followed by concatenation or bitwise operators; regression tests cover those controls. The full local Python 3.10–3.14 test matrix passes (512 passed per version). Thanks!