Fix CardDAV URL construction for contacts

- Add _build_url helper to properly construct URLs from paths
- Fix test.sh to pass addressbook_id when listing contacts
- Prevents path duplication when addressbook_id is a full path

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

test.sh

@@ -74,10 +74,16 @@ echo -e "\n[6/7] Listing address books..."
 ADDRESSBOOKS=$(mcp_request 5 "tools/call" '{"name":"list_addressbooks","arguments":{}}')
 echo "$ADDRESSBOOKS"
 
-# List contacts
+# List contacts (using first addressbook from previous response)
 echo -e "\n[7/7] Listing contacts..."
-CONTACTS=$(mcp_request 6 "tools/call" '{"name":"list_contacts","arguments":{"limit":10}}')
-echo "$CONTACTS"
+# Extract first addressbook ID from previous response
+ADDRESSBOOK_ID=$(echo "$ADDRESSBOOKS" | grep -o '"id":"[^"]*"' | head -1 | cut -d'"' -f4)
+if [ -n "$ADDRESSBOOK_ID" ]; then
+    CONTACTS=$(mcp_request 6 "tools/call" "{\"name\":\"list_contacts\",\"arguments\":{\"addressbook_id\":\"$ADDRESSBOOK_ID\",\"limit\":10}}")
+    echo "$CONTACTS"
+else
+    echo "No addressbook found to list contacts from"
+fi
 
 echo -e "\n================================"
 echo "All tests completed!"