[toml] Merge TOMLMojo into Decimo as a sub-package

[forfudan]

This PR merges the previously standalone TOML parser (“tomlmojo”) into the Decimo codebase as the decimo.toml subpackage, updating tests, scripts, CI, and documentation to use the new import path.

Changes:

• Add TOML tokenizer/parser implementation under src/decimo/toml/ and re-export the public API from decimo.toml.
• Update test sources and test runner scripts to use decimo.toml (and move TOML tests under tests/toml/).
• Remove standalone tomlmojo packaging steps from Pixi tasks and GitHub Actions; update docs/readmes accordingly.

[Copilot]

Pull request overview

This PR merges the previously standalone TOML parser (“tomlmojo”) into the Decimo codebase as the decimo.toml subpackage, updating tests, scripts, CI, and documentation to use the new import path.

Changes:

• Add TOML tokenizer/parser implementation under src/decimo/toml/ and re-export the public API from decimo.toml.
• Update test sources and test runner scripts to use decimo.toml (and move TOML tests under tests/toml/).
• Remove standalone tomlmojo packaging steps from Pixi tasks and GitHub Actions; update docs/readmes accordingly.

Reviewed changes

Copilot reviewed 28 out of 30 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/toml/test_decimo_toml.mojo	Switch TOML parser usage to decimo.toml API in the TOML feature test suite.
tests/test_toml.sh	Update test runner to execute TOML tests from tests/toml/.
tests/test_all.sh	Replace test_tomlmojo.sh invocation with test_toml.sh.
tests/decimal128/test_decimal128_sqrt.mojo	Update TOML document type reference to decimo.toml.parser.TOMLDocument.
tests/decimal128/test_decimal128_round.mojo	Same TOML type update; minor signature formatting.
tests/decimal128/test_decimal128_root_power.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_multiply.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_modulo.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_logarithm.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_from_string.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_from_int.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_factorial.mojo	Update TOML document type reference import.
tests/decimal128/test_decimal128_divide.mojo	Update TOML document type reference import; helper signature formatting.
tests/decimal128/test_decimal128_conversions.mojo	Update TOML document type reference import.
tests/bigdecimal/test_bigdecimal_trigonometric.mojo	Update TOML document type reference import in helper signature.
src/decimo/toml/tokenizer.mojo	Introduce TOML tokenizer implementation within Decimo package.
src/decimo/toml/parser.mojo	Introduce TOML parser + document/value types and parse helpers.
src/decimo/toml/init.mojo	Rename/document package and re-export TOML API from subpackage.
src/decimo/tests.mojo	Repoint test infra TOML parsing to decimo.toml and update types/docs.
python/pyproject.toml	Reorder metadata fields (no functional change expected).
python/README.md	Adjust status table formatting/content.
pixi.toml	Remove standalone tomlmojo packaging/cleanup; update TOML test task.
docs/readme_zht.md	Update Chinese README to point to built-in TOML parser docs.
docs/readme_unreleased.md	Update project structure section to reflect decimo.toml integration.
docs/readme_toml.md	Rename and update TOML parser documentation for decimo.toml.
docs/plans/mojo4py.md	Refresh Python packaging layout/build task naming.
benches/decimal128/bench_quantize.mojo	Update comment to reference decimo.toml.
benches/decimal128/bench_comparison.mojo	Update comment to reference decimo.toml.
README.md	Update top-level README to reference built-in decimo.toml.
.github/workflows/run_tests.yaml	Remove tomlmojo packaging step; rename/update TOML test job/script.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.