sprint-4: Project Editor + .appack compiler + IRudderActuator HAL + dual sensor config

Cherry-pick of ab28cb7 onto main (was missing from main branch history).

Python:
- arautopilot/core/sensor_config.py: RudderSensorConfig + DualRudderSensorConfig
  (AS5048A SPI / potentiometer, dual with cross-validation thresholds)
- arautopilot/core/vessel_config.py: add sensors: DualRudderSensorConfig field
- arautopilot/studio/compiler/appack.py: .appack compiler (ZIP with
  manifest.json + project.yaml + firmware_config.h + install_notes.txt)
- arautopilot/studio/editors/project_editor.py: full project config editor
  (vessel / actuator / sensors / PID, RBAC-gated fields, save/load .yaml/.json)
- arautopilot/studio/main_window.py: wire ProjectEditorWidget into Project tab
- tests: test_sensor_config.py (11 tests) + test_appack_compiler.py (10 tests)

Firmware:
- hal/rudder_actuator_iface.h: IRudderActuator abstract interface
- hal/rudder_actuator_hydraulic.h: reversible hydraulic pump (LEDC PWM)
- hal/rudder_actuator_electric.h: reversible DC motor + deadband compensation
- hal/rudder_actuator_factory.h: build-time type selection via AR_ACTUATOR_TYPE

Tests: 483 passed (was 462, +21 Sprint 4)

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

arautopilot/core/vessel_config.py

@@ -13,6 +13,7 @@ from pydantic import BaseModel, ConfigDict, Field
 from arautopilot.core.actuator_config import ActuatorConfig
 from arautopilot.core.ids import VesselId, new_vessel_id
 from arautopilot.core.pid_config import PidConfig
+from arautopilot.core.sensor_config import DualRudderSensorConfig, RudderSensorConfig, RudderSensorType
 
 
 class VesselType(StrEnum):
@@ -60,3 +61,13 @@ class VesselConfig(BaseModel):
 
     actuator: ActuatorConfig
     pid: PidConfig
+    sensors: DualRudderSensorConfig = Field(
+        default_factory=lambda: DualRudderSensorConfig(
+            primary=RudderSensorConfig(
+                type=RudderSensorType.AS5048A_SPI,
+                label="Primary – rudder stock",
+                spi_cs_gpio=10,
+            )
+        ),
+        description="Rudder angle sensor(s). Dual config enables cross-validation and failover.",
+    )