fix(embedded): build abi3 wheel for Python 3.11+ compatibility

[polaz]

Problem

coordinode-embedded is published only with cp311 wheels for Linux. Google Colab runs Python 3.12, so pip cannot find a compatible wheel and installation fails.

CalledProcessError: Command 'pip install coordinode-embedded' returned non-zero exit status 1

Root Cause

pyo3 in coordinode-embedded/Cargo.toml uses the default per-interpreter ABI. maturin builds one wheel per Python interpreter found on the runner. CI uses Python 3.11 for Linux builds → only cp311 wheels.

Solution

Enable abi3 stable ABI via abi3-py311 feature flag on pyo3. maturin detects this automatically and builds a single cp311-abi3 wheel per platform that works on Python 3.11, 3.12, 3.13, 3.14+.

One-line change: coordinode-embedded/Cargo.toml

Acceptance Criteria

• cp311-abi3 wheel on PyPI for Linux x86_64, Linux aarch64, macOS arm64, macOS x86_64, Windows x86_64
• pip install coordinode-embedded succeeds on Colab (Python 3.12)

[coderabbitai]

🔗 Related PRs

#8 - fix(coordinode): fix empty wheel — use sources mapping instead of packages [merged]
#40 - ci(release): fix embedded wheel builds for Windows, macOS, and Linux aarch64 [merged]
#58 - fix(ci): set PYO3_CROSS_PYTHON_VERSION for aarch64 Linux cross-compilation [merged]
#60 - fix(ci): remove PYO3_CROSS_PYTHON_VERSION, use pypa manylinux image for aarch64 [merged]
#64 - fix(demo): install coordinode-embedded from PyPI wheel, drop rustup/Rust build [closed]

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