Stage 0: Repository und Architekturgrundlage

- Pyproject.toml mit FastAPI, Pydantic v2, SQLAlchemy, httpx, asyncio,
  BeautifulSoup4, selectolax, trafilatura, uvicorn, pytest-asyncio
- Multi-stage Dockerfile (Python 3.12-slim, Non-Root-User nsct)
- docker-compose.yml (nsct-api + postgres + optional searxng)
- .env.example mit allen Config-Parametern
- Config-System: AppSettings mit LLMConfig, VisionConfig, AudioConfig,
  DatabaseConfig — komplett aus Environment, keine Hardcodes
- Strukturiertes Logging mit research_id/llm_request_id Tracking
- Pydantic v2 Schemas: SearchQuery, Source, Claim, EvidenceRelation,
  CitationEdge, ResearchReport
- SQLAlchemy 2.0 Declarative Models + async Engine Factory
- SSRF-Schutz: URL-Validation, IP-Blocklist (RFC1918, Cloud Metadata,
  file://, ftp://)
- Provider-Interfaces: LLMProvider, VisionProvider, AudioProvider,
  SearchProvider, ContentFetcher als ABCs
- Health-Endpoints: /health, /ready (LLM-Connect-Test), /providers
- FastAPI App mit CORS, lifespan (LLM Pre-Flight)
- CLI-Stub mit Entry-Points: nsct, nsct-core, nsct-api
- 6 Test-Cases: /health, /ready, /providers + No-Secrets-Test
- Vollständige Dokumentation: README, ARCHITECTURE, SECURITY,
  METHODOLOGY, API, DEPLOYMENT
- .gitignore (Python, Docker, IDE, .env)

src/nsct/api/main.py

@@ -0,0 +1,81 @@
+"""FastAPI application — entry point for the API server."""
+
+from __future__ import annotations
+
+import logging
+from contextlib import asynccontextmanager
+
+import httpx
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from nsct.config import AppSettings
+
+logger = logging.getLogger(__name__)
+
+
+# ---------------------------------------------------------------------------
+# Lifespan
+# ---------------------------------------------------------------------------
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan — startup and shutdown hooks."""
+    config: AppSettings = app.state.config
+
+    logger.info("NSCT API starting up — version %s", app.state.version)
+
+    # Pre-flight: validate LLM connectivity
+    llm_base = config.llm.base_url if config and config.llm and config.llm.base_url else ""
+    if llm_base:
+        try:
+            async with httpx.AsyncClient(timeout=5.0) as client:
+                resp = await client.get(f"{llm_base}/models")
+                if resp.status_code == 200:
+                    logger.info("LLM provider reachable — model endpoint returned 200")
+                else:
+                    logger.warning("LLM provider returned %s", resp.status_code)
+        except Exception as exc:
+            logger.warning("LLM connectivity check failed: %s", exc)
+
+    yield
+
+
+# ---------------------------------------------------------------------------
+# App factory
+# ---------------------------------------------------------------------------
+
+
+def create_app() -> FastAPI:
+    """Create the FastAPI application with all routes and middleware."""
+    config = AppSettings.from_env()
+
+    app = FastAPI(
+        title="NSCT API",
+        description="Neutral Search Crawler Tool — API server",
+        version="0.1.0",
+        docs_url="/docs" if config.debug else None,
+        redoc_url="/redoc" if config.debug else None,
+        lifespan=lifespan,
+    )
+    app.state.config = config
+    app.state.version = "0.1.0"
+
+    # CORS — allow local development
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["http://localhost:3000", "http://localhost:5173", "http://127.0.0.1:3000"],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+    # Mount health router
+    from nsct.api.health import router as health_router
+    app.include_router(health_router, tags=["system"])
+
+    return app
+
+
+app = create_app()