fix: add MEALIE_INTERNAL_URL env var for Docker-to-Docker API calls

When deployed behind Cloudflare Tunnel, requests from the container to
the external Mealie URL fail with 530 (hairpin). MEALIE_INTERNAL_URL
lets the container use the Docker-internal address (e.g. http://mealie:9000)
for API calls while keeping the external URL for browser links.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/config.py

@@ -7,6 +7,10 @@ from pathlib import Path
 DATA_DIR = Path(os.environ.get("DATA_DIR", "/data"))
 CONFIG_FILE = DATA_DIR / "config.json"
 
+# Optional internal URL for Docker-to-Docker API calls (avoids Cloudflare hairpin).
+# The user-facing mealie_url is still used for browser links.
+MEALIE_INTERNAL_URL = os.environ.get("MEALIE_INTERNAL_URL", "").strip().rstrip("/")
+
 _DEFAULTS = {
     "mealie_url": "",
     "mealie_api_key": "",