fix(lint): resolve all ruff E402/I001/F821 errors

- Move pytestmark after all imports in 35 test files (E402: not-at-top)
- Add TYPE_CHECKING guard for FlightProcessor in composition.py (F821)
- Sort import blocks in src/ and tests/ (I001 auto-fix via ruff --fix)
- ruff check src/ tests/ now exits 0 with no errors

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/gps_denied/components/gpr/__init__.py

@@ -6,9 +6,9 @@ re-exported as ``IGlobalPlaceRecognition``.
 """
 
 from gps_denied.components.gpr.faiss_gpr import (  # noqa: F401
+    _FAISS_AVAILABLE,
     GlobalPlaceRecognition,
     _faiss,
-    _FAISS_AVAILABLE,
 )
 from gps_denied.components.gpr.protocol import (  # noqa: F401
     IGlobalPlaceRecognition,

src/gps_denied/components/mavlink_io/__init__.py

@@ -1,12 +1,12 @@
+from .mock_mavlink import MockMAVConnection
 from .protocol import MAVLinkBridgeProtocol
 from .pymavlink_bridge import (
-    MAVLinkBridge,
     _PYMAVLINK_AVAILABLE,
-    _unix_to_gps_time,
+    MAVLinkBridge,
     _confidence_to_fix_type,
     _eskf_to_gps_input,
+    _unix_to_gps_time,
 )
-from .mock_mavlink import MockMAVConnection
 
 __all__ = [
     "MAVLinkBridgeProtocol",

src/gps_denied/components/vio/__init__.py

@@ -12,19 +12,19 @@ the legacy ``core/vo.py`` monolith into per-backend modules:
 The legacy ``gps_denied.core.vo`` import path is preserved as a thin
 re-export shim for one phase; tests still import from there.
 """
-from gps_denied.components.vio.protocol import (
-    ISequentialVisualOdometry,
-    VisualOdometry,
-)
-from gps_denied.components.vio.orbslam_backend import (
-    ORBVisualOdometry,
-    SequentialVisualOdometry,
-)
 from gps_denied.components.vio.cuvslam_backend import (
     CuVSLAMMonoDepthVisualOdometry,
     CuVSLAMVisualOdometry,
 )
 from gps_denied.components.vio.factory import create_vo_backend
+from gps_denied.components.vio.orbslam_backend import (
+    ORBVisualOdometry,
+    SequentialVisualOdometry,
+)
+from gps_denied.components.vio.protocol import (
+    ISequentialVisualOdometry,
+    VisualOdometry,
+)
 
 __all__ = [
     "VisualOdometry",

src/gps_denied/config.py

@@ -181,7 +181,7 @@ class AppSettings(BaseSettings):
     def settings_customise_sources(cls, settings_cls, **kwargs):
         """Load YAML overlay from config/{env}.yaml when present."""
         import os
-        import yaml
+
 
         init_kwargs = kwargs.get("init_settings")
         env_settings = kwargs.get("env_settings")

src/gps_denied/core/gpr.py

@@ -1,11 +1,11 @@
 """Legacy import path for GPR. Phase 1 shim — code lives in components/gpr/."""
-from gps_denied.components.gpr.protocol import (
-    IGlobalPlaceRecognition,  # noqa: F401
-)
 from gps_denied.components.gpr.faiss_gpr import (
+    _FAISS_AVAILABLE,
     GlobalPlaceRecognition,
     _faiss,
-    _FAISS_AVAILABLE,
+)
+from gps_denied.components.gpr.protocol import (
+    IGlobalPlaceRecognition,  # noqa: F401
 )
 
 __all__ = [

src/gps_denied/core/graph.py

@@ -1,5 +1,5 @@
 """Legacy import path. Phase 1 shim — code lives in core/factor_graph.py."""
 from gps_denied.core.factor_graph import (  # noqa: F401
-    IFactorGraphOptimizer,
     FactorGraphOptimizer,
+    IFactorGraphOptimizer,
 )

src/gps_denied/core/mavlink.py

@@ -4,18 +4,18 @@ CRITICAL: tests/test_mavlink.py and tests/test_gps_input_encoding.py import
 private helpers from this path. Per PATTERNS.md §6.2, the underscore names
 MUST be re-exported here verbatim or 12+ tests break.
 """
+from gps_denied.components.mavlink_io.mock_mavlink import (  # noqa: F401
+    MockMAVConnection,
+)
 from gps_denied.components.mavlink_io.protocol import (  # noqa: F401
     MAVLinkBridgeProtocol,
 )
 from gps_denied.components.mavlink_io.pymavlink_bridge import (  # noqa: F401
-    MAVLinkBridge,
     _PYMAVLINK_AVAILABLE,
-    _unix_to_gps_time,
+    MAVLinkBridge,
     _confidence_to_fix_type,
     _eskf_to_gps_input,
-)
-from gps_denied.components.mavlink_io.mock_mavlink import (  # noqa: F401
-    MockMAVConnection,
+    _unix_to_gps_time,
 )
 
 __all__ = [

src/gps_denied/core/metric.py

@@ -1,10 +1,10 @@
 """Legacy import path. Phase 1 shim — code lives in components/satellite_matcher/."""
-from gps_denied.components.satellite_matcher.protocol import (  # noqa: F401
-    MetricRefiner,
-    IMetricRefinement,
-)
 from gps_denied.components.satellite_matcher.metric_refinement import (  # noqa: F401
     MetricRefinement,
 )
+from gps_denied.components.satellite_matcher.protocol import (  # noqa: F401
+    IMetricRefinement,
+    MetricRefiner,
+)
 
 __all__ = ["MetricRefinement", "IMetricRefinement", "MetricRefiner"]

src/gps_denied/core/processor.py

@@ -1,6 +1,6 @@
 """Legacy import path. Phase 1 shim — code lives in pipeline/orchestrator.py."""
 from gps_denied.pipeline.orchestrator import (  # noqa: F401
     FlightProcessor,
-    TrackingState,
     FrameResult,
+    TrackingState,
 )

src/gps_denied/hot_types/frame_state.py

@@ -15,7 +15,7 @@ introduces this type.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Optional, TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from gps_denied.schemas import GPSPoint

src/gps_denied/pipeline/__init__.py

@@ -1,9 +1,9 @@
 """Pipeline package: orchestrator + IO + composition root."""
-from .orchestrator import FlightProcessor
+from .composition import build_pipeline
 from .image_input import ImageInputPipeline
+from .orchestrator import FlightProcessor
 from .result_manager import ResultManager
 from .sse_streamer import SSEEventStreamer
-from .composition import build_pipeline
 
 Pipeline = FlightProcessor
 

src/gps_denied/pipeline/composition.py

@@ -15,10 +15,13 @@ Env-conditional wiring
 from __future__ import annotations
 
 import logging
-from typing import Optional
+from typing import TYPE_CHECKING
 
 from gps_denied.obs import configure_logging
 
+if TYPE_CHECKING:
+    from gps_denied.pipeline.orchestrator import FlightProcessor
+
 logger = logging.getLogger(__name__)
 
 

src/gps_denied/pipeline/orchestrator.py

@@ -16,10 +16,10 @@ import structlog
 from structlog.contextvars import bind_contextvars, clear_contextvars
 
 from gps_denied.core.eskf import ESKF
+from gps_denied.db.repository import FlightRepository
 from gps_denied.pipeline.image_input import ImageInputPipeline
 from gps_denied.pipeline.result_manager import ResultManager
 from gps_denied.pipeline.sse_streamer import SSEEventStreamer
-from gps_denied.db.repository import FlightRepository
 from gps_denied.schemas import CameraParameters, GPSPoint
 from gps_denied.schemas.flight import (
     BatchMetadata,

src/gps_denied/pipeline/result_manager.py

@@ -4,8 +4,8 @@ from __future__ import annotations
 
 from datetime import datetime
 
-from gps_denied.pipeline.sse_streamer import SSEEventStreamer
 from gps_denied.db.repository import FlightRepository
+from gps_denied.pipeline.sse_streamer import SSEEventStreamer
 from gps_denied.schemas import GPSPoint
 from gps_denied.schemas.events import FrameProcessedEvent