Feature: Panel Fixed Effects (PanelRegression experiment class)

[drbenvincent]

Summary

Add a PanelRegression experiment with fixed effects support, diagnostics, and docs.

Closes #627

Changes

• Add PanelRegression experiment with within/dummies FE and plotting helpers
• Export the new experiment and add validation/plot data tests
• Add a panel fixed effects notebook and docs index entry
• Refresh the interrogate badge from pre-commit

Testing

• pre-commit run --all-files
• python -m pytest causalpy/tests/ -x -v

Checklist

• Pre-commit checks pass
• All tests pass
• Documentation updated (if applicable)
• Follows project coding conventions

---

📚 Documentation preview 📚: https://causalpy--670.org.readthedocs.build/en/670/

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[drbenvincent]

• Initial stab at the docs notebook was poor.
  • Did not conform to the structure laid out in the issue, and one of the plot functions errored.
  • References section didn't work because of incorrect citation format
  • Text uses hard wrapping with line breaks, but it should use soft wrapping without the new lines. Let auto word wrap take care of that.
• Code seems pretty good. But no docstrings.

[codecov]

Codecov Report

❌ Patch coverage is 39.42029% with 209 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.94%. Comparing base (b5de507) to head (a13f90a).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
causalpy/experiments/panel_regression.py	33.86%	195 Missing and 14 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #670      +/-   ##
==========================================
- Coverage   94.38%   91.94%   -2.44%     
==========================================
  Files          44       46       +2     
  Lines        7517     7862     +345     
  Branches      456      511      +55     
==========================================
+ Hits         7095     7229     +134     
- Misses        261      457     +196     
- Partials      161      176      +15     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[drbenvincent]

I should work through a bunch of examples and see how the functionality compares to related packages

[read-the-docs-community]

Documentation build overview

📚 causalpy | 🛠️ Build #31148705 | 📁 Comparing a13f90a against latest (b5de507)

🔍 Preview build

Show files changed (25 files in total): 📝 7 modified | ➕ 18 added | ➖ 0 deleted

File	Status
404.html	📝 modified
genindex.html	📝 modified
py-modindex.html	📝 modified
_modules/index.html	📝 modified
knowledgebase/quasi_dags.html	📝 modified
notebooks/index.html	📝 modified
notebooks/panel_fixed_effects_pymc.html	➕ added
api/generated/causalpy.experiments.html	📝 modified
api/generated/causalpy.experiments.panel_regression.PanelRegression.init.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.effect_summary.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.fit.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.get_plot_data.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.get_plot_data_bayesian.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.get_plot_data_ols.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.input_validation.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.plot.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.plot_coefficients.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.plot_residuals.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.plot_trajectories.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.plot_unit_effects.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.print_coefficients.html	➕ added
api/generated/causalpy.experiments.panel_regression.PanelRegression.summary.html	➕ added
api/generated/causalpy.experiments.panel_regression.html	➕ added
_modules/causalpy/experiments/panel_regression.html	➕ added

[drbenvincent]

Superseded by #628. Same feature (PanelRegression for #627); we're consolidating on #628, which has the review fixes, correct __init__ pipeline, and full test coverage.