chore: add PyPI publish workflow and update install instructions

CI runs lint + tests on Python 3.9/3.12 for push/PR to main.
Publish job triggers on v* tags using trusted publishing.

Author: syzygyhack

.github/workflows/workflow.yml

@@ -0,0 +1,59 @@
+name: CI & Publish
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.12"]
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev,viz]"
+
+      - name: Lint
+        run: ruff check src/ tests/
+
+      - name: Test
+        run: pytest tests/ -v
+
+  publish:
+    needs: test
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/v')
+    permissions:
+      id-token: write
+    environment:
+      name: pypi
+      url: https://pypi.org/p/fisher-simplex
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Build
+        run: |
+          python -m pip install --upgrade pip build
+          python -m build
+
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1

README.md

@@ -14,17 +14,21 @@ Need a different language than Python? `fisher-simplex` maintains a [SPEC.md](/S
 
 ## Installation
 
-Not yet published to PyPI. Install from source:
-
 ```bash
-git clone <repo-url> && cd fisher-simplex
-uv sync            # or: pip install -e .
+pip install fisher-simplex
 ```
 
 For visualization support:
 
 ```bash
-uv sync --extra viz   # or: pip install -e ".[viz]"
+pip install "fisher-simplex[viz]"
+```
+
+Or install from source:
+
+```bash
+git clone <repo-url> && cd fisher-simplex
+pip install -e ".[dev,viz]"
 ```
 
 ## Quick usage