Fix ruff I001 import sorting errors across 7 files after moving
_cpp_parser into Grammar/. Update cibuildwheel config: test-requires
as array, per-platform before-build commands.

poetry install doesn't invoke scikit-build-core to compile the C++
extension. Use pip install . (with build isolation) after installing
deps to actually build the .so module. Update version.yml to not
require poetry for version extraction.

Testing workflow: copy the compiled C++ extension from site-packages
back to the source tree so mypy can resolve the import.

Ubuntu 24.04: use --no-deps to avoid upgrading system numpy/pandas
which causes binary incompatibility errors.

The YAML folded scalar (>) was preserving leading whitespace in the
python -c command, causing IndentationError. Use single-line command.

Use follow_imports = "silent" for vtlengine.AST.* in mypy config
to suppress errors from AST files when the C++ extension .so isn't
in the source tree (CI builds install to site-packages only).
Remove the copy C++ extension step from the testing workflow.

Instead of silencing all AST modules, target only:
- _cpp_parser: follow_imports=silent (handles missing .so in CI)
- ASTConstructor + ASTConstructorModules: disallow_untyped_calls=false

No need to build the C++ parser just to check version consistency.
Extract __version__ with grep and pyproject version with tomllib,
removing the ANTLR download and pip install steps entirely.

Pure bash version check using grep — no Python, no build needed.

Use actions/cache to store the built wheel keyed on OS, Python
version, and hash of C++ source files. On cache hit, ANTLR download
and C++ compilation are skipped entirely — only the wheel install
runs.

The missing .so cascades errors through all AST files, not just
the constructor. Use follow_imports=silent for vtlengine.AST.*
which matches the existing exclude pattern's intent.

- Define ANTLR4CPP_STATIC to avoid dllimport errors on Windows
- Use /w instead of -w for MSVC warning suppression
- Broaden mypy follow_imports=silent to all vtlengine.AST.*

Not needed for parsing and causes MSVC build errors with
high_resolution_clock on Windows.

ProfilingATNSimulator is referenced by other ANTLR runtime code, so
it can't be excluded. Use /FI"chrono" on MSVC to fix the missing
high_resolution_clock symbol.

Use setup-python's built-in poetry cache for faster dependency
installs. Combine dependency install and wheel install into one step.

Phase 0: Infrastructure - cached py::object refs for all 44 AST classes,
ScalarType classes, Model classes, SemanticError. Helper functions for
token info extraction, node type checking, and Python class construction.

Phase 1: Port all 50 Terminal visitor methods from Terminals.py to C++,
including visitConstant, visitVarID, visitComponentID, visitBasicScalarType,
visitWindowingClause, and all other leaf-level visitors.

Phase 2: Port all 48 ExprComponent visitor methods from ExprComponents.py
to C++, including visitExprComponent (recursive dispatch), all function
component visitors (string, numeric, time, comparison, conditional,
aggregate, analytic), and the cast/eval operators.

All 4037 tests pass. The C++ functions are exposed as pybind11 bindings
but not yet wired into the main AST construction path - the Python
visitor still runs unchanged.

Implement all 81 dataset-level expression visitors in C++:
- visitExpr dispatch and all expression alternatives
- Join functions (inner/left/cross/full join with clause handling)
- Dataset clauses (rename, calc, filter, keep/drop, pivot/unpivot, subspace, aggr)
- String, numeric, comparison, time, conditional functions
- Set functions (union, intersect, diff, symdiff, setdiff)
- Hierarchy and validation functions
- Aggregate and analytic functions with grouping clauses
- de_ruleset_elements dict mutation for validation operators

Implement all 18 top-level visitor methods in C++:
- visitStart entry point with statement collection
- visitStatement dispatch (temporary/persist assignment, define expression)
- Operator definition with parameter items and return types
- Datapoint ruleset definition with signature and rule clauses
- Hierarchical ruleset definition with code item relations
- build_ast() now calls visitStart() for full tree walk
- Initialize missing cached AST class refs (Argument, Operator, HRBinOp, etc.)

- Replace ASTVisitor().visitStart() with C++ build_ast() in create_ast()
- Fix default Windowing to use raw ints (-1, 0) matching Python behavior
  (create_windowing normalizes to strings, but ASTString checks for ints)
- Fix visitSignedInteger overflow: use stoll instead of stoi for large numbers

- Add ASTBuilder::cleanup() to release all cached Python class references
- Add cleanup_phase3() for Phase 3 statics
- Use stoll instead of stoi for large integer support in visitSignedInteger
- Fix default Windowing to preserve raw ints matching Python behavior

…::object refs

Static py::object destructors were calling Py_DECREF after Python interpreter
finalization, causing a segfault in __run_exit_handlers. Replace assignment
with .release() (sets internal PyObject* to nullptr without Py_DECREF) and
register cleanup via atexit from Python side so it runs while the interpreter
is still alive.

Delete ASTConstructor.py, ASTConstructorModules/, _rule_constants.py,
60+ unused visit_* pybind11 bindings, ~190 token/rule constants, and
the backwards-compat ASTVisitor import. Only ML_COMMENT constant kept
(used by ASTComment.py for prettify). Total: -5,942 lines.