Refactor piecewise polynomial (implement GEP-8) (#1132)

Refactor piecewise polynomial YAML and code for GEP-08, twin to [TTSIM #76](ttsim-dev/ttsim#76)
    
Convert all piecewise polynomial YAML parameters from numbered dict
format
to ordered lists with explicit interval strings:
- solidaritätszuschlag, einkommensteuertarif, vorsorge, behinderung,
  wohngeld, grundrente, bürgergeld/arbeitslosengeld_2 freibeträge,
  lohnsteuer vorsorge
- Rename keys: rate_linear->slope, rate_quadratic->quadratic,
  intercept_at_lower_threshold->intercept
- Update Python code to use new API (parameter_list instead of
  parameter_dict, new key names)
- Fix rates shape indexing: [coeff, interval] -> [interval, coeff]
  in lohnsteuer.py and solidaritätszuschlag.py
- Add extend_extend_intervals_to_real_line to fix stale adjacent
intervals
  after upsert_tree merges in param_functions
- Re-export extend_extend_intervals_to_real_line from gettsim.tt
- Aside: Lots of infrastructure updates.

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Marvin Immesberger <immesberger@posteo.de>
Co-authored-by: Marvin Immesberger <74215010+MImmesberger@users.noreply.github.com>

Author: 4 people

.ai-instructions

@@ -12,21 +12,6 @@ on:
     branches:
       - '*'
 jobs:
-  run-ty:
-    name: Run ty
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6
-      - uses: prefix-dev/setup-pixi@v0.9.4
-        with:
-          pixi-version: v0.63.2
-          cache: true
-          cache-write: ${{ github.event_name == 'push' && github.ref_name == 'main' }}
-          frozen: true
-          environments: py314
-      - name: Run ty
-        run: pixi run -e py314 ty
-        shell: bash -el {0}
   run-tests:
     name: Run tests for ${{ matrix.os }} on ${{ matrix.environment }}
     runs-on: ${{ matrix.os }}
@@ -60,7 +45,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.62.2
+          pixi-version: v0.66.0
           cache: true
           cache-write: ${{ github.event_name == 'push' && github.ref_name == 'main' }}
           frozen: true
@@ -70,22 +55,40 @@ jobs:
           matrix.environment == 'py311' ||
           matrix.environment == 'py312' ||
           matrix.environment == 'py313'
-        run: pixi run -e ${{ matrix.environment }} tests
+        run: pixi run --locked -e ${{ matrix.environment }} tests
         shell: bash -el {0}
       - name: Run tests on Linux (with NumPy backend and coverage)
         if: runner.os == 'Linux' && matrix.environment == 'py314'
-        run: pixi run -e ${{ matrix.environment }} tests --cov --cov-report=xml
+        run: pixi run --locked -e ${{ matrix.environment }} tests-with-cov
         shell: bash -el {0}
       - name: Run tests on MacOS / Windows (with NumPy backend and without coverage)
         if: runner.os != 'Linux'
-        run: pixi run -e ${{ matrix.environment }} tests
+        run: pixi run --locked -e ${{ matrix.environment }} tests
         shell: bash -el {0}
       - name: Run tests with JAX backend
         if: matrix.environment == 'py314-jax'
-        run: pixi run -e ${{ matrix.environment }} tests-jax
+        run: pixi run --locked -e ${{ matrix.environment }} tests-jax
         shell: bash -el {0}
       - name: Upload coverage reports
         if: runner.os == 'Linux' && matrix.environment == 'py314'
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v5.5.2
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+  run-ty:
+    name: Run ty
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: prefix-dev/setup-pixi@v0.9.4
+        with:
+          pixi-version: v0.66.0
+          cache: true
+          cache-write: ${{ github.event_name == 'push' && github.ref_name == 'main' }}
+          frozen: true
+          environments: type-checking type-checking-jax
+      - name: Run ty
+        run: pixi run --locked ty
+        shell: bash -el {0}
+      - name: Run ty-jax
+        run: pixi run --locked ty-jax
+        shell: bash -el {0}

.github/workflows/main.yaml .github/workflows/main.yml.github/workflows/main.yaml renamed to .github/workflows/main.yml

@@ -28,6 +28,6 @@ jobs:
           --outdir dist/
       - name: Publish distribution 📦 to PyPI
         if: startsWith(github.ref, 'refs/tags')
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@v1.13.0
         with:
           attestations: true

.github/workflows/publish-to-pypi.yaml .github/workflows/publish-to-pypi.yml.github/workflows/publish-to-pypi.yaml renamed to .github/workflows/publish-to-pypi.yml

@@ -21,14 +21,16 @@ docs/_build/
 .idea/
 .vscode/
 
-# Jupyter
+# Jupyter / Jupyter Book
 .ipynb_checkpoints/
+_build
 
 # macOS
 .DS_Store
 
 # pixi
 .pixi/
+node_modules/
 
 # Python
 __pycache__/

.gitignore

@@ -0,0 +1,4 @@
+[submodule ".ai-instructions"]
+	path = .ai-instructions
+	url = https://github.com/OpenSourceEconomics/ai-instructions.git
+	branch = make-submodule

.gitmodules

@@ -6,30 +6,42 @@ repos:
       - id: check-useless-excludes
       # - id: identity  # Prints all files passed to pre-commits. Debugging.
   - repo: https://github.com/tox-dev/pyproject-fmt
-    rev: v2.12.1
+    rev: v2.19.0
     hooks:
       - id: pyproject-fmt
   - repo: https://github.com/lyz-code/yamlfix
     rev: 1.19.1
     hooks:
       - id: yamlfix
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.37.0
+    hooks:
+      - id: check-github-workflows
+      - id: check-jsonschema
+        name: Validate JSON/YAML files against schema
+        entry: check-jsonschema
+        language: python
+        files: ^src/gettsim/germany/.*\.(yaml|yml)$
+        args:
+          - --schemafile=docs/geps/params-schema.json
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v6.0.0
     hooks:
       - id: check-added-large-files
         args:
           - --maxkb=10000
+      - id: check-ast
       - id: check-case-conflict
+      - id: check-docstring-first
       - id: check-merge-conflict
+      - id: check-toml
       - id: check-vcs-permalinks
       - id: check-yaml
-      - id: check-toml
       - id: debug-statements
       - id: end-of-file-fixer
       - id: fix-byte-order-marker
         types:
           - text
-      - id: forbid-submodules
       - id: mixed-line-ending
         args:
           - --fix=lf
@@ -39,14 +51,12 @@ repos:
           - --branch
           - main
       - id: trailing-whitespace
-      - id: check-ast
-      - id: check-docstring-first
   - repo: https://github.com/adrienverge/yamllint.git
     rev: v1.38.0
     hooks:
       - id: yamllint
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.15.0
+    rev: v0.15.6
     hooks:
       - id: ruff-check
         args:
@@ -61,7 +71,7 @@ repos:
           - pyi
           - python
   - repo: https://github.com/kynan/nbstripout
-    rev: 0.9.0
+    rev: 0.9.1
     hooks:
       - id: nbstripout
         args:
@@ -78,10 +88,7 @@ repos:
         args:
           - --wrap
           - '88'
-        files: (CLAUDE\.md|README\.md)
-  - repo: https://github.com/executablebooks/mdformat
-    rev: 1.0.0
-    hooks:
+        files: (AGENTS\.md|CLAUDE\.md|README\.md|CHANGES\.md|CODE_OF_CONDUCT\.md|modules/.*\.md|profiles/.*\.md)
       - id: mdformat
         additional_dependencies:
           - mdformat-myst
@@ -90,15 +97,5 @@ repos:
           - --wrap
           - '88'
         files: (docs/.|CHANGES.md|CODE_OF_CONDUCT.md)
-  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.36.1
-    hooks:
-      - id: check-jsonschema
-        name: Validate JSON/YAML files against schema
-        entry: check-jsonschema
-        language: python
-        files: ^src/gettsim/germany/.*\.(yaml|yml)$
-        args:
-          - --schemafile=docs/geps/params-schema.json
 ci:
   autoupdate_schedule: monthly