diff --git a/.gitea/workflows/build.yaml b/.gitea/workflows/build.yaml
index 80acc27..aeeb5c1 100644
--- a/.gitea/workflows/build.yaml
+++ b/.gitea/workflows/build.yaml
@@ -28,10 +28,10 @@ jobs:
         run: |
           pip3 install -r requirements.txt ruff
 
-#      - name: Run ruff linter
-#        shell: sh
-#        run: |
-#          ruff check SPARC/ tests/
+      - name: Run ruff linter
+        shell: sh
+        run: |
+          ruff check SPARC/ tests/
 
       - name: Install Node.js and check TypeScript types
         shell: sh
@@ -47,16 +47,17 @@ jobs:
           fi
           npx tsc --noEmit
 
-#      - name: Run pytest
-#        shell: sh
-#        env:
-#          DATABASE_URL: "sqlite://"
-#          API_KEY: "test-key"
-#          OPENROUTER_API_KEY: "test-key"
-#          JWT_SECRET: "test-secret-for-ci"
-#          APP_ENV: "development"
-#        run: |
-#          python3 -m pytest tests/ -v --tb=short -x
+      - name: Run pytest
+        shell: sh
+        env:
+          DATABASE_URL: "sqlite://"
+          API_KEY: "test-key"
+          OPENROUTER_API_KEY: "test-key"
+          JWT_SECRET: "test-secret-for-ci"
+          APP_ENV: "development"
+        run: |
+          pip3 install pytest
+          python3 -m pytest tests/ -v --tb=short -x
 
   build-api:
     needs: test
diff --git a/SPARC/analyzer.py b/SPARC/analyzer.py
index 31ad7f1..1ebceaf 100644
--- a/SPARC/analyzer.py
+++ b/SPARC/analyzer.py
@@ -10,13 +10,13 @@ from concurrent.futures import ThreadPoolExecutor, as_completed
 from typing import Callable
 
 from SPARC import config
-
-logger = logging.getLogger(__name__)
 from SPARC.database import DatabaseClient
 from SPARC.llm import LLMAnalyzer
 from SPARC.serp_api import SERP
 from SPARC.types import BatchAnalysisResult, CompanyAnalysisResult, Patent, Patents
 
+logger = logging.getLogger(__name__)
+
 
 class CompanyAnalyzer:
     """Orchestrates end-to-end company performance analysis via patents."""
diff --git a/SPARC/api.py b/SPARC/api.py
index 3a28033..a42ddd7 100644
--- a/SPARC/api.py
+++ b/SPARC/api.py
@@ -3,9 +3,14 @@
 Provides REST API endpoints for analyzing company patent portfolios.
 """
 
+from __future__ import annotations
+
 from contextlib import asynccontextmanager
 from datetime import datetime
-from typing import Annotated, List
+from typing import TYPE_CHECKING, Annotated, List
+
+if TYPE_CHECKING:
+    from SPARC.database import DatabaseClient
 
 from fastapi import BackgroundTasks, Depends, FastAPI, HTTPException, Query, Request
 from fastapi.middleware.cors import CORSMiddleware
@@ -653,7 +658,6 @@ async def export_company_pdf(
         PDF file download
     """
     import io
-    import textwrap
 
     from reportlab.lib import colors
     from reportlab.lib.pagesizes import letter
diff --git a/tests/test_auth.py b/tests/test_auth.py
index de79259..bb4378a 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -175,6 +175,7 @@ class TestGetMe:
         from datetime import timedelta
 
         import jwt as pyjwt
+
         from SPARC.auth import JWT_ALGORITHM, JWT_SECRET
 
         payload = {
diff --git a/tests/test_rate_limit.py b/tests/test_rate_limit.py
index f9f06af..8d0adf0 100644
--- a/tests/test_rate_limit.py
+++ b/tests/test_rate_limit.py
@@ -1,7 +1,8 @@
 """Tests for rate limiting on auth endpoints."""
 
+from unittest.mock import MagicMock, patch
+
 import pytest
-from unittest.mock import Mock, patch, MagicMock
 from fastapi.testclient import TestClient
 
 from SPARC.api import app
diff --git a/tests/test_security.py b/tests/test_security.py
index b6e4be1..b34deec 100644
--- a/tests/test_security.py
+++ b/tests/test_security.py
@@ -14,6 +14,7 @@ class TestJWTSecretStartupCheck:
         with patch.dict(os.environ, {"APP_ENV": "production"}):
             # Reload config to pick up the new APP_ENV
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
 
@@ -31,6 +32,7 @@ class TestJWTSecretStartupCheck:
         """Starting with default secret and APP_ENV=development must not raise."""
         with patch.dict(os.environ, {"APP_ENV": "development"}):
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
 
@@ -46,6 +48,7 @@ class TestJWTSecretStartupCheck:
         """Starting with a custom secret in production must not raise."""
         with patch.dict(os.environ, {"APP_ENV": "production"}):
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
 
@@ -65,6 +68,7 @@ class TestJWTSecretStartupCheck:
             env.pop("APP_ENV", None)
             with patch.dict(os.environ, env, clear=True):
                 import importlib
+
                 import SPARC.config
                 importlib.reload(SPARC.config)
 
@@ -84,6 +88,7 @@ class TestCORSConfig:
         """When CORS_ORIGINS is unset, defaults to localhost origins."""
         with patch.dict(os.environ, {"CORS_ORIGINS": ""}):
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
             assert SPARC.config.cors_origins == [
@@ -95,6 +100,7 @@ class TestCORSConfig:
         """Setting CORS_ORIGINS configures allowed origins."""
         with patch.dict(os.environ, {"CORS_ORIGINS": "https://sparc.example.com,https://app.example.com"}):
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
             assert SPARC.config.cors_origins == [
@@ -109,6 +115,7 @@ class TestCORSConfig:
         """A single origin without comma works correctly."""
         with patch.dict(os.environ, {"CORS_ORIGINS": "https://sparc.example.com"}):
             import importlib
+
             import SPARC.config
             importlib.reload(SPARC.config)
             assert SPARC.config.cors_origins == ["https://sparc.example.com"]