Release prep v0.1.0: tests, CI (test + build), fix stationary_density overflow, implement plot_trajectories, README/packaging polish

[Copilot]

The repo was not release-ready: no tests, no CI, a stubbed public method, a numerical bug in stationary_density, overstated README claims, and no root-level install metadata.

Fixes

Bug: stationary_density numerical overflow
exp(-2V/σ²) overflowed when V had large negative values, producing inf/NaN in the normalised density. Fixed by shifting V to V - min(V) before exponentiation (mathematically equivalent after normalisation).

plot_trajectories was a bare pass stub
Implemented with a single/dual-panel matplotlib figure (optional energy panel via show_energy=True); returns the Figure object.

Added

Tests — tests/test_engine.py, 27 deterministic/seeded tests:

• find_fixed_points: residual correctness, stability sign, structure, edge cases
• escape_probability: unit-interval bounds, threshold sensitivity
• stationary_density: normalisation, non-negativity, peak location vs. equilibrium
• seat_and_release: key structure, control-zeroed-after-release, raises on no bowl
• simulate: reproducibility, boundedness, energy recording
• plot_trajectories: returns figure, handles single/multiple realizations

CI — .github/workflows/ci.yml, permissions: contents: read, two jobs:

• test: runs pytest tests/ -v across Python 3.9–3.12
• build (runs after test): builds wheel + sdist via python -m build, verifies the wheel installs and imports cleanly, uploads dist/ as a workflow artifact

Root-level pyproject.toml — enables pip install -e ".[dev]" from repo root; requires-python aligned to >=3.9 (3.8 EOL Oct 2024); project.license uses SPDX string form to avoid setuptools deprecation warning

Root-level .gitignore — excludes dist/, build/, *.egg-info/, caches, and virtualenvs

Docs / metadata

• README: replaced absolute claims ("holds it forever", "force any stochastic system", "near-zero by default") with precise language; added Quick Start example
• CITATION.cff: added version: "0.1.0"
• release/CHANGELOG.md: updated

Packaging note: Legacy packaging/pyproject.toml is preserved alongside the new root pyproject.toml. Standard tooling uses the root one; packaging/ can be removed in a follow-up.

[beanapologist]

automate test and build

[Copilot]

automate test and build

Done. The CI workflow now has two jobs:

• test — runs pytest tests/ -v across Python 3.9–3.12
• build (runs after test) — installs build, produces a wheel + sdist via python -m build, verifies the wheel installs and imports cleanly, then uploads the dist/ directory as a workflow artifact

Also fixed the project.license TOML-table deprecation in pyproject.toml (now uses the SPDX string form) and added a root .gitignore to exclude build artifacts (dist/, build/, *.egg-info/). Commit: the latest push.