Add basic backend infrastructure

Signed-off-by: Felipe Cardoso <felipe.cardoso@hotmail.it>

backend/app/main.py

@@ -0,0 +1,29 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routes import training, samples
+from app.core.config import settings
+
+app = FastAPI(
+    title="Training Monitor API",
+    description="API for monitoring ML training progress and samples",
+    version="1.0.0",
+)
+
+# Configure CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # In production, replace with specific origins
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers with versioning
+app.include_router(training.router, prefix=f"{settings.API_VER_STR}/training", tags=["training"])
+app.include_router(samples.router, prefix=f"{settings.API_VER_STR}/samples", tags=["samples"])
+
+
+@app.get("/health")
+async def health_check():
+    return {"status": "healthy"}