feat: initial p2pkg tool with CI, ruff, and stable tagging

https://chatgpt.com/share/69468609-0584-800f-a3e0-9d58210fb0e8

.github/workflows/ci-and-stable.yml

@@ -0,0 +1,106 @@
+name: CI (tests + ruff) and stable tag
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+
+permissions:
+  contents: write
+
+jobs:
+  test:
+    name: unittest (py${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+
+      - name: Install (editable)
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e .
+
+      - name: Run tests
+        run: |
+          make test
+
+  ruff:
+    name: ruff (py3.12)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+
+      - name: Install (editable) + ruff
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e .
+          pip install ruff
+
+      - name: Ruff check
+        run: |
+          ruff check .
+
+      # Optional: falls du ruff format nutzt
+      # - name: Ruff format (check)
+      #   run: |
+      #     ruff format --check .
+
+  stable:
+    name: Tag stable (if version commit)
+    runs-on: ubuntu-latest
+    needs: [test, ruff]
+    if: >
+      github.event_name == 'push' &&
+      github.ref == 'refs/heads/main' &&
+      github.repository_owner == 'kevinveenbirkenbach'
+    steps:
+      - name: Checkout (full history for tags)
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Check commit message for version
+        id: version
+        shell: bash
+        run: |
+          set -euo pipefail
+          msg="$(git log -1 --pretty=%B)"
+          echo "Commit message:"
+          echo "$msg"
+          if echo "$msg" | grep -Eq '(^|[^0-9])(v?[0-9]+\.[0-9]+\.[0-9]+)([^0-9]|$)'; then
+            echo "has_version=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "has_version=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Update stable tag
+        if: steps.version.outputs.has_version == 'true'
+        shell: bash
+        run: |
+          set -euo pipefail
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+          # Force-update lightweight tag "stable" to current commit
+          git tag -f stable
+
+          # Push (force) the tag
+          git push -f origin stable