Python Bindings + Fallback Float Parsing Fix

[vincentlaucsb]

Summary

Adds first-class Python bindings for the CSV parser under the fastpycsv package name, plus a few C++ parser improvements that support the Python work.

Python

• Added fastpycsv.reader() with lazy C++-backed row objects
• Added materialized row iterators for lists, tuples, and dicts, including bounded-memory chunk iteration
• Added bulk materialization helpers for lists, tuples, and dicts
• Added fast NumPy materialization APIs:
  • fastpycsv.read_numpy(...)
  • fastpycsv.read_numpy_batches(...)
• Added native predicate support for filtering before materialization
• Added fastpycsv.write_csv(...)
• Added Python docs using Furo, linked from the generated C++ docs
• Added Python package metadata, cibuildwheel wheel builds, dry-run CI, and PyPI trusted publishing workflow
• Renamed the package from the internal csvpy naming to the PyPI-ready fastpycsv
• Added Python tests for reader behavior, lazy rows, materialized iterators, NumPy output, predicates, writer behavior, and compatibility wrappers

C++

• Added eager field classification support so parser-side type classification can be reused by higher-level consumers
• Fixed floating-point parsing behavior when std::from_chars() floating support is unavailable
• Added supporting tests for eager classification and fallback floating-point parsing behavior

Verification

• Python unit tests pass locally
• Python docs build successfully
• cibuildwheel dry run passes on Windows, macOS, and Ubuntu
• Source distribution build passes
• Wheel metadata validation passes
• Existing C++ tests pass
• PyPI publishing is gated to published GitHub releases with version/tag validation

[codecov]

Codecov Report

❌ Patch coverage is 91.71429% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.12%. Comparing base (e730e89) to head (a8926df).

Files with missing lines	Patch %	Lines
include/internal/memory/field_scalar_list.hpp	80.00%	1 Missing and 6 partials ⚠️
python/fastpycsv/_format.py	79.16%	5 Missing ⚠️
python/fastpycsv/__init__.py	90.24%	4 Missing ⚠️
python/fastpycsv/_reader.py	96.52%	4 Missing ⚠️
include/internal/parser/orchestrator.hpp	50.00%	0 Missing and 2 partials ⚠️
include/internal/speculative/parallel_parser.hpp	66.66%	2 Missing ⚠️
python/fastpycsv/_writer.py	86.66%	2 Missing ⚠️
include/internal/csv_row.cpp	90.00%	0 Missing and 1 partial ⚠️
include/internal/csv_row.hpp	94.44%	0 Missing and 1 partial ⚠️
include/internal/parser/core.hpp	92.30%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #316      +/-   ##
==========================================
+ Coverage   89.56%   91.12%   +1.56%     
==========================================
  Files          39       47       +8     
  Lines        2922     3346     +424     
  Branches     1106      942     -164     
==========================================
+ Hits         2617     3049     +432     
- Misses         93      130      +37     
+ Partials      212      167      -45     

Flag	Coverage Δ
cpp	90.93% <87.71%> (?)
python	93.64% <93.64%> (?)

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