refactor: реструктуризация — core/, db/, routes/, web/

guarddog_nexus/
├── core/          scanner, harvester, nexus, llm
├── db/            engine, models, queries
├── routes/        webhooks, api_*, web
└── web/           templates + static

- 11 файлов перемещено (git mv — сохранена история)
- Все импорты обновлены (~15 файлов)
- main.py, tests — исправлены пути
- 50/50 тестов, ruff clean

guarddog_nexus/main.py

@@ -7,13 +7,13 @@ import uvicorn
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
 
-from guarddog_nexus.api import findings, packages, scans
 from guarddog_nexus.config import config
 from guarddog_nexus.constants import APP_DESCRIPTION, APP_NAME, APP_PACKAGE, STATIC_MOUNT_PATH
-from guarddog_nexus.database import init_db
+from guarddog_nexus.db.engine import init_db
 from guarddog_nexus.logging_setup import log
-from guarddog_nexus.web.routes import router as web_router
-from guarddog_nexus.webhooks import router as webhook_router
+from guarddog_nexus.routes import api_findings, api_packages, api_scans
+from guarddog_nexus.routes.web import router as web_router
+from guarddog_nexus.routes.webhooks import router as webhook_router
 
 STATIC_DIR = os.path.join(os.path.dirname(__file__), "web", "static")
 
@@ -34,9 +34,9 @@ app = FastAPI(
 )
 
 app.include_router(webhook_router)
-app.include_router(scans.router)
-app.include_router(packages.router)
-app.include_router(findings.router)
+app.include_router(api_scans.router)
+app.include_router(api_packages.router)
+app.include_router(api_findings.router)
 app.include_router(web_router)
 
 if os.path.isdir(STATIC_DIR):