feat(api): add REST API with 45+ endpoints

- Add workers API for pool management
- Add jobs API for queue operations
- Add scan-rules API for CRUD operations
- Add scanner API for control and status
- Add settings API for configuration management
- Add system API for resource monitoring
- Add filesystem API for path browsing
- Add setup wizard API endpoint

backend/api/system.py

@@ -0,0 +1,210 @@
+"""System resources monitoring API."""
+import logging
+import psutil
+from typing import List, Optional
+from fastapi import APIRouter
+from pydantic import BaseModel
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/api/system", tags=["system"])
+
+
+# === RESPONSE MODELS ===
+
+class CPUInfo(BaseModel):
+    """CPU information."""
+    usage_percent: float
+    count_logical: int
+    count_physical: int
+    frequency_mhz: Optional[float] = None
+
+
+class MemoryInfo(BaseModel):
+    """Memory information."""
+    total_gb: float
+    used_gb: float
+    free_gb: float
+    usage_percent: float
+
+
+class GPUInfo(BaseModel):
+    """GPU information."""
+    id: int
+    name: str
+    memory_total_mb: Optional[int] = None
+    memory_used_mb: Optional[int] = None
+    memory_free_mb: Optional[int] = None
+    utilization_percent: Optional[int] = None
+
+
+class SystemResourcesResponse(BaseModel):
+    """System resources response."""
+    cpu: CPUInfo
+    memory: MemoryInfo
+    gpus: List[GPUInfo]
+
+
+# === ROUTES ===
+
+@router.get("/resources", response_model=SystemResourcesResponse)
+async def get_system_resources():
+    """
+    Get current system resources (CPU, RAM, GPU).
+
+    Returns:
+        System resources information
+    """
+    # CPU info
+    cpu_percent = psutil.cpu_percent(interval=0.1)
+    cpu_count_logical = psutil.cpu_count(logical=True)
+    cpu_count_physical = psutil.cpu_count(logical=False)
+    cpu_freq = psutil.cpu_freq()
+
+    cpu_info = CPUInfo(
+        usage_percent=cpu_percent,
+        count_logical=cpu_count_logical or 0,
+        count_physical=cpu_count_physical or 0,
+        frequency_mhz=cpu_freq.current if cpu_freq else 0
+    )
+
+    # Memory info
+    mem = psutil.virtual_memory()
+    memory_info = MemoryInfo(
+        total_gb=round(mem.total / (1024**3), 2),
+        used_gb=round(mem.used / (1024**3), 2),
+        free_gb=round(mem.available / (1024**3), 2),
+        usage_percent=round(mem.percent, 1)
+    )
+
+    # GPU info - try to detect NVIDIA GPUs
+    gpus = []
+    try:
+        import pynvml
+        pynvml.nvmlInit()
+        device_count = pynvml.nvmlDeviceGetCount()
+
+        for i in range(device_count):
+            handle = pynvml.nvmlDeviceGetHandleByIndex(i)
+            name = pynvml.nvmlDeviceGetName(handle)
+            memory_info_gpu = pynvml.nvmlDeviceGetMemoryInfo(handle)
+            utilization = pynvml.nvmlDeviceGetUtilizationRates(handle)
+
+            gpus.append(GPUInfo(
+                id=i,
+                name=name if isinstance(name, str) else name.decode('utf-8'),
+                memory_total_mb=memory_info_gpu.total // (1024**2),
+                memory_used_mb=memory_info_gpu.used // (1024**2),
+                memory_free_mb=memory_info_gpu.free // (1024**2),
+                utilization_percent=utilization.gpu
+            ))
+
+        pynvml.nvmlShutdown()
+    except Exception as e:
+        logger.debug(f"Could not get GPU info: {e}")
+        # No GPUs or pynvml not available
+        pass
+
+    return SystemResourcesResponse(
+        cpu=cpu_info,
+        memory=memory_info,
+        gpus=gpus
+    )
+
+
+@router.get("/cpu", response_model=CPUInfo)
+async def get_cpu_info():
+    """Get CPU information."""
+    cpu_percent = psutil.cpu_percent(interval=0.1)
+    cpu_count_logical = psutil.cpu_count(logical=True)
+    cpu_count_physical = psutil.cpu_count(logical=False)
+    cpu_freq = psutil.cpu_freq()
+
+    return CPUInfo(
+        usage_percent=cpu_percent,
+        count_logical=cpu_count_logical or 0,
+        count_physical=cpu_count_physical or 0,
+        frequency_mhz=cpu_freq.current if cpu_freq else 0
+    )
+
+
+@router.get("/memory", response_model=MemoryInfo)
+async def get_memory_info():
+    """Get memory information."""
+    mem = psutil.virtual_memory()
+
+    return MemoryInfo(
+        total_gb=round(mem.total / (1024**3), 2),
+        used_gb=round(mem.used / (1024**3), 2),
+        free_gb=round(mem.available / (1024**3), 2),
+        usage_percent=round(mem.percent, 1)
+    )
+
+
+@router.get("/gpus", response_model=List[GPUInfo])
+async def get_gpus_info():
+    """Get all GPUs information."""
+    gpus = []
+    try:
+        import pynvml
+        pynvml.nvmlInit()
+        device_count = pynvml.nvmlDeviceGetCount()
+
+        for i in range(device_count):
+            handle = pynvml.nvmlDeviceGetHandleByIndex(i)
+            name = pynvml.nvmlDeviceGetName(handle)
+            memory_info_gpu = pynvml.nvmlDeviceGetMemoryInfo(handle)
+            utilization = pynvml.nvmlDeviceGetUtilizationRates(handle)
+
+            gpus.append(GPUInfo(
+                id=i,
+                name=name if isinstance(name, str) else name.decode('utf-8'),
+                memory_total_mb=memory_info_gpu.total // (1024**2),
+                memory_used_mb=memory_info_gpu.used // (1024**2),
+                memory_free_mb=memory_info_gpu.free // (1024**2),
+                utilization_percent=utilization.gpu
+            ))
+
+        pynvml.nvmlShutdown()
+    except Exception as e:
+        logger.debug(f"Could not get GPU info: {e}")
+
+    return gpus
+
+
+@router.get("/gpu/{device_id}", response_model=GPUInfo)
+async def get_gpu_info(device_id: int):
+    """Get specific GPU information."""
+    try:
+        import pynvml
+        pynvml.nvmlInit()
+
+        handle = pynvml.nvmlDeviceGetHandleByIndex(device_id)
+        name = pynvml.nvmlDeviceGetName(handle)
+        memory_info_gpu = pynvml.nvmlDeviceGetMemoryInfo(handle)
+        utilization = pynvml.nvmlDeviceGetUtilizationRates(handle)
+
+        gpu = GPUInfo(
+            id=device_id,
+            name=name if isinstance(name, str) else name.decode('utf-8'),
+            memory_total_mb=memory_info_gpu.total // (1024**2),
+            memory_used_mb=memory_info_gpu.used // (1024**2),
+            memory_free_mb=memory_info_gpu.free // (1024**2),
+            utilization_percent=utilization.gpu
+        )
+
+        pynvml.nvmlShutdown()
+        return gpu
+
+    except Exception as e:
+        logger.error(f"Could not get GPU {device_id} info: {e}")
+        # Return basic info if can't get details
+        return GPUInfo(
+            id=device_id,
+            name=f"GPU {device_id}",
+            memory_total_mb=None,
+            memory_used_mb=None,
+            memory_free_mb=None,
+            utilization_percent=None
+        )
+