ci: add composite actions from poetry

.github/actions/bootstrap-poetry/action.yaml

@@ -0,0 +1,48 @@
+name: Bootstrap Poetry
+description: Configure the environment with the specified Python and Poetry version.
+
+inputs:
+  python-version:
+    description: Desired node-semver compatible Python version expression (or 'default')
+    default: 'default'
+  python-latest:
+    description: Use an uncached Python if a newer match is available
+    default: 'false'
+  python-prereleases:
+    description: Allow usage of pre-release Python versions
+    default: 'false'
+  poetry-spec:
+    description: pip-compatible installation specification to use for Poetry
+    default: 'poetry'
+
+outputs:
+  python-path:
+    description: Path to the installed Python interpreter
+    value: ${{ steps.setup-python.outputs.python-path }}
+  python-version:
+    description: Version of the installed Python interpreter
+    value: ${{ steps.setup-python.outputs.python-version }}
+
+runs:
+  using: composite
+  steps:
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5
+      id: setup-python
+      if: inputs.python-version != 'default'
+      with:
+        python-version: ${{ inputs.python-version }}
+        check-latest: ${{ inputs.python-latest == 'true' }}
+        allow-prereleases: ${{ inputs.python-prereleases == 'true' }}
+        update-environment: false
+
+    - run: >
+        pipx install \
+          ${{ inputs.python-version != 'default' && format('--python "{0}"', steps.setup-python.outputs.python-path) || '' }} \
+          '${{ inputs.poetry-spec }}'
+      shell: bash
+
+    # Enable handling long path names (+260 char) on the Windows platform
+    # https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#maximum-path-length-limitation
+    - run: git config --system core.longpaths true
+      if: runner.os == 'Windows'
+      shell: pwsh

.github/actions/poetry-install/action.yaml

@@ -0,0 +1,57 @@
+name: Poetry Install
+description: Run `poetry install` with optional artifact and metadata caching
+
+inputs:
+  args:
+    description: Arguments for `poetry install`
+  cache:
+    description: Enable transparent Poetry artifact and metadata caching
+    default: 'true'
+  path:
+    description: Path to Poetry project
+    default: '.'
+
+outputs:
+  cache-hit:
+    description: Whether an exact cache hit occured
+    value: ${{ steps.cache.outputs.cache-hit }}
+
+defaults:
+  run:
+    working-directory: ${{ inputs.path }}
+
+runs:
+  using: composite
+  steps:
+    - run: printf 'cache-dir=%s\n' "$(poetry config cache-dir)" >> $GITHUB_OUTPUT
+      id: poetry-config
+      shell: bash
+
+    # Bust the cache every 24 hours to prevent it from expanding over time.
+    - run: printf 'date=%s\n' "$(date -I)" >> $GITHUB_OUTPUT
+      id: get-date
+      if: inputs.cache == 'true'
+      shell: bash
+
+    - uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9 # v4
+      id: cache
+      if: inputs.cache == 'true'
+      with:
+        path: |
+          ${{ steps.poetry-config.outputs.cache-dir }}/artifacts
+          ${{ steps.poetry-config.outputs.cache-dir }}/cache
+        key: poetry-${{ steps.get-date.outputs.date }}-${{ runner.os }}-${{ hashFiles(format('{0}/pyproject.toml', inputs.path), format('{0}/poetry.lock', inputs.path)) }}
+        # The cache is cross-platform, and other platforms are used to seed cache misses.
+        restore-keys: |
+          poetry-${{ steps.get-date.outputs.date }}-${{ runner.os }}-
+          poetry-${{ steps.get-date.outputs.date }}-
+        enableCrossOsArchive: true
+
+    - run: poetry install ${{ inputs.args }}
+      shell: bash
+
+    - run: poetry env info
+      shell: bash
+
+    - run: poetry show
+      shell: bash