refactor: split main.py into modules (config, database, models, utils, auth, runtime, maintenance)

main.py was ~3000 lines with models, routes, Docker ops, maintenance all mixed.
Split into 7 focused modules:
- config.py: env vars and constants
- database.py: SQLAlchemy engine, SessionLocal, Base, get_db
- models.py: ORM models and enums
- utils.py: logging, formatting, icon handling, misc helpers
- auth.py: password hashing, cookies, CSRF, user dependency
- runtime.py: all Docker operations, pool management, session lifecycle
- maintenance.py: cleanup loop, schema bootstrap, startup logic
- main.py: FastAPI app, middleware, all route handlers only

app/config.py

@@ -0,0 +1,35 @@
+import os
+from pathlib import Path
+
+DATABASE_URL = os.getenv("DATABASE_URL", "postgresql+psycopg2://portal:portal@db:5432/portal")
+COOKIE_NAME = "portal_auth"
+CSRF_COOKIE = "csrf_token"
+COOKIE_MAX_AGE = 8 * 60 * 60
+SESSION_IDLE_SECONDS = int(os.getenv("SESSION_IDLE_SECONDS", "7200"))
+PUBLIC_HOST = os.getenv("PUBLIC_HOST", "stend.4mont.ru")
+LOG_LEVEL = os.getenv("LOG_LEVEL", "INFO").upper()
+LOG_SLOW_REQUEST_MS = int(os.getenv("LOG_SLOW_REQUEST_MS", "2000"))
+GO_USER_LOCK_TIMEOUT_SECONDS = float(os.getenv("GO_USER_LOCK_TIMEOUT_SECONDS", "8.0"))
+GO_POOL_LOCK_TIMEOUT_SECONDS = float(os.getenv("GO_POOL_LOCK_TIMEOUT_SECONDS", "20.0"))
+POOL_DISPATCH_RETRIES = int(os.getenv("POOL_DISPATCH_RETRIES", "6"))
+POOL_DISPATCH_REQUEST_TIMEOUT_SECONDS = float(os.getenv("POOL_DISPATCH_REQUEST_TIMEOUT_SECONDS", "2.0"))
+POOL_DISPATCH_SLEEP_SECONDS = float(os.getenv("POOL_DISPATCH_SLEEP_SECONDS", "0.3"))
+TRAEFIK_INTERNAL_URL = os.getenv("TRAEFIK_INTERNAL_URL", "http://traefik")
+PREWARM_POOL_SIZE = int(os.getenv("PREWARM_POOL_SIZE", "2"))
+UNIVERSAL_POOL_SIZE = int(os.getenv("UNIVERSAL_POOL_SIZE", "0"))
+WEB_POOL_SIZE = int(os.getenv("WEB_POOL_SIZE", "20"))
+WEB_POOL_BUFFER = int(os.getenv("WEB_POOL_BUFFER", "2"))
+X11VNC_FLAGS = os.getenv("X11VNC_FLAGS", "-wait 5 -defer 5 -threads")
+MAX_ACTIVE_SERVICES_PER_USER = int(os.getenv("MAX_ACTIVE_SERVICES_PER_USER", "4"))
+WEB_RESOLUTION_MIN_WIDTH = int(os.getenv("WEB_RESOLUTION_MIN_WIDTH", "1024"))
+WEB_RESOLUTION_MIN_HEIGHT = int(os.getenv("WEB_RESOLUTION_MIN_HEIGHT", "720"))
+WEB_RESOLUTION_MAX_WIDTH = int(os.getenv("WEB_RESOLUTION_MAX_WIDTH", "3840"))
+WEB_RESOLUTION_MAX_HEIGHT = int(os.getenv("WEB_RESOLUTION_MAX_HEIGHT", "2160"))
+ENABLE_STARTUP_MAINTENANCE = os.getenv("ENABLE_STARTUP_MAINTENANCE", "1") == "1"
+ICON_UPLOAD_MAX_BYTES = 2 * 1024 * 1024
+ICON_UPLOAD_TYPES = {
+    "image/png": "png",
+    "image/jpeg": "jpg",
+    "image/webp": "webp",
+}
+SERVICE_ICONS_DIR = Path("static/service-icons")