Improve CI: Add Python 3.13, optimize linting, and fix unused import

.github/workflows/ci.yml

@@ -5,14 +5,15 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
+  workflow_dispatch:
 
 jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
 
     steps:
       - uses: actions/checkout@v4
@@ -36,11 +37,13 @@ jobs:
           pip install -e ".[dev]"
 
       - name: Run linting
+        if: matrix.python-version == '3.12'
         run: |
           ruff check .
           ruff format --check .
 
       - name: Run type checking
+        if: matrix.python-version == '3.12'
         run: |
           mypy headroom --ignore-missing-imports
 
@@ -87,7 +90,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.10"
 
       - name: Install build tools
         run: |

tests/test_proxy_compression_headers.py

@@ -10,8 +10,6 @@
 
 import pytest
 
-from headroom.proxy.server import ProxyConfig
-
 
 @pytest.fixture
 def mock_anthropic_response_with_compression_headers():