ci: optimize GitHub Actions performance (#30)

Implements multiple optimizations to reduce CI time and resource usage:

- Split linting into dedicated job (runs once instead of 5x per matrix)
- Add Python package caching to all workflows
- Add concurrency groups to cancel outdated PR runs
- Remove redundant test job from release workflow (CI already tests)
- Add path filters to skip CI for docs-only changes on main

Expected improvements:
- ~80% faster linting (1 job vs 5 jobs)
- ~50% faster releases (no redundant testing)
- Faster dependency installation (Python caching)
- Reduced CI queue times (concurrency cancellation)
- No wasted runs for documentation updates

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: dreamiurg

.github/workflows/ci.yml

@@ -3,10 +3,56 @@ name: CI
 on:
   push:
     branches: [main]
+    # Skip CI for docs-only changes on push to main
+    paths-ignore:
+      - '**.md'
+      - 'docs/**'
+      - 'examples/**'
+      - '.github/**'
+      - '!.github/workflows/**'
   pull_request:
     branches: [main]
+    # Always run on PRs (for review), but individual jobs can skip if needed
+
+# Cancel in-progress runs when a new workflow with the same group name starts
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
 
 jobs:
+  # Separate lint job - runs once instead of on every matrix combination
+  lint:
+    name: Lint and format check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.14"
+          cache: pip
+          cache-dependency-path: pyproject.toml
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          enable-cache: true
+          cache-dependency-glob: "pyproject.toml"
+
+      - name: Install dependencies
+        run: uv sync --extra dev
+
+      - name: Run ruff check
+        run: uv run ruff check peakbagger tests
+
+      - name: Run ruff format check
+        run: uv run ruff format --check peakbagger tests
+
+      - name: Run mypy
+        run: uv run mypy peakbagger --pretty
+        continue-on-error: true
+
   test:
     name: Test on ${{ matrix.os }} - Python ${{ matrix.python-version }}
     runs-on: ${{ matrix.os }}
@@ -30,6 +76,8 @@ jobs:
         uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
+          cache: pip
+          cache-dependency-path: pyproject.toml
 
       - name: Install uv
         uses: astral-sh/setup-uv@v5
@@ -40,16 +88,6 @@ jobs:
       - name: Install dependencies
         run: uv sync --extra dev
 
-      - name: Run ruff check
-        run: uv run ruff check peakbagger tests
-
-      - name: Run ruff format check
-        run: uv run ruff format --check peakbagger tests
-
-      - name: Run mypy
-        run: uv run mypy peakbagger --pretty
-        continue-on-error: true
-
       - name: Run tests with coverage
         run: uv run pytest --cov=peakbagger --cov-report=xml --cov-report=term
 

.github/workflows/release.yml

@@ -9,32 +9,9 @@ permissions:
   contents: write  # Required for semantic-release to create releases and push commits
 
 jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Set up Python
-        uses: actions/setup-python@v6
-        with:
-          python-version: '3.12'
-
-      - name: Install uv
-        uses: astral-sh/setup-uv@v5
-        with:
-          enable-cache: true
-          cache-dependency-glob: "pyproject.toml"
-
-      - name: Install dependencies
-        run: uv sync
-
-      - name: Run tests
-        run: uv run pytest -v
-
+  # Skip test job - CI workflow already runs comprehensive tests on push to main
   release:
     runs-on: ubuntu-latest
-    needs: test
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -46,6 +23,8 @@ jobs:
         uses: actions/setup-python@v6
         with:
           python-version: '3.12'
+          cache: pip
+          cache-dependency-path: pyproject.toml
 
       - name: Install uv
         uses: astral-sh/setup-uv@v5