feat: add get_vlans, get_gateway_interfaces tools and billing config fallback

- Add get_vlans tool to filter interfaces by type=vlan
- Add get_gateway_interfaces tool to identify gateway interfaces from routes
- Add fallback to billing-mcp/config.json when router not in devices.json
- Update .gitignore to exclude venv, pycache, snapshots

debug_api.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+import requests
+import json
+import sys
+import os
+
+# Import from our existing app
+from app.update_data import get_base_url
+
+DEVICES_FILE = "devices.json"
+
+def test_router(router):
+    name = router["name"]
+    host = router["host"]
+    port = router["port"]
+    user = router["user"]
+    password = router["pass"]
+    
+    base_url = get_base_url(host, port)
+    auth = (user, password)
+    
+    print(f"\n{'='*60}")
+    print(f"TESTING ROUTER: {name} ({host})")
+    print(f"{'='*60}")
+    
+    endpoints = ["system/identity", "system/resource", "interface"]
+    
+    for ep in endpoints:
+        url = f"{base_url}/{ep}"
+        print(f"\n📡 Requesting: {url}")
+        
+        try:
+            response = requests.get(
+                url, 
+                auth=auth, 
+                headers={"Accept": "application/json"},
+                timeout=15
+            )
+            
+            print(f"✅ Status Code: {response.status_code}")
+            # print(f"Headers: {dict(response.headers)}")
+            
+            if response.status_code == 200:
+                try:
+                    data = response.json()
+                    print(f"🟢 Success! Received {len(str(data))} bytes of JSON data.")
+                    if isinstance(data, list) and len(data) > 0:
+                        print(f"Sample data keys: {list(data[0].keys()) if isinstance(data[0], dict) else 'not a dict'}")
+                except Exception as e:
+                    print(f"🟡 Status 200 but JSON Parse Error: {e}")
+                    print(f"Raw Content (First 200 chars): {response.text[:200]}")
+            else:
+                print(f"🔴 Failed with status {response.status_code}")
+                print(f"Error Body: {response.text}")
+                
+        except requests.exceptions.ConnectTimeout:
+            print("❌ Connection Timeout: Could not reach the router.")
+        except requests.exceptions.ConnectionError as e:
+            print(f"❌ Connection Error: {e}")
+        except Exception as e:
+            print(f"❌ Unexpected Error ({type(e).__name__}): {e}")
+
+if __name__ == "__main__":
+    if not os.path.exists(DEVICES_FILE):
+        print(f"Error: {DEVICES_FILE} not found.")
+        sys.exit(1)
+        
+    with open(DEVICES_FILE, 'r') as f:
+        devices = json.load(f)
+        
+    if len(sys.argv) > 1:
+        target = sys.argv[1].lower()
+        devices = [d for d in devices if target in d["name"].lower() or target in d["host"]]
+        if not devices:
+            print(f"No router found matching '{target}'")
+            sys.exit(1)
+
+    for device in devices:
+        test_router(device)