fix(form-compile): port bugfixes to Python — Number/Date in lists, UserVisible for Ref

Port PS1 bugfixes to Python:
- Document List: add Номер + Дата as first columns
- Hidden Ref: userVisible=false instead of visible=false (both Catalog and Document lists)
- Emitter: support <UserVisible><xr:Common>false</xr:Common></UserVisible>
- Add userVisible to KNOWN_KEYS

Note: new_field_element calls in Python were already correct (no Bug 1 equivalent).
Python snapshots updated.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/skills/cases/form-compile-from-object/snapshots/document-item-medium/Documents/АктВыполненныхВнутреннихРабот/Forms/ФормаДокумента.xml

@@ -1,21 +1 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<MetaDataObject xmlns="http://v8.1c.ru/8.3/MDClasses" xmlns:app="http://v8.1c.ru/8.2/managed-application/core" xmlns:cfg="http://v8.1c.ru/8.1/data/enterprise/current-config" xmlns:cmi="http://v8.1c.ru/8.2/managed-application/cmi" xmlns:ent="http://v8.1c.ru/8.1/data/enterprise" xmlns:lf="http://v8.1c.ru/8.2/managed-application/logform" xmlns:style="http://v8.1c.ru/8.1/data/ui/style" xmlns:sys="http://v8.1c.ru/8.1/data/ui/fonts/system" xmlns:v8="http://v8.1c.ru/8.1/data/core" xmlns:v8ui="http://v8.1c.ru/8.1/data/ui" xmlns:web="http://v8.1c.ru/8.1/data/ui/colors/web" xmlns:win="http://v8.1c.ru/8.1/data/ui/colors/windows" xmlns:xen="http://v8.1c.ru/8.3/xcf/enums" xmlns:xpr="http://v8.1c.ru/8.3/xcf/predef" xmlns:xr="http://v8.1c.ru/8.3/xcf/readable" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.17">
-	<Form uuid="UUID-001">
-		<Properties>
-			<Name>ФормаДокумента</Name>
-			<Synonym>
-				<v8:item>
-					<v8:lang>ru</v8:lang>
-					<v8:content>ФормаДокумента</v8:content>
-				</v8:item>
-			</Synonym>
-			<Comment/>
-			<FormType>Managed</FormType>
-			<IncludeHelpInContents>false</IncludeHelpInContents>
-			<UsePurposes>
-				<v8:Value xsi:type="app:ApplicationUsePurpose">PlatformApplication</v8:Value>
-				<v8:Value xsi:type="app:ApplicationUsePurpose">MobilePlatformApplication</v8:Value>
-			</UsePurposes>
-		</Properties>
-	</Form>
-</MetaDataObject>
+<?xml version="1.0" encoding="utf-8"?><MetaDataObject version="2.17"><Form uuid="UUID-001"><Properties><Name>ФормаДокумента</Name><Synonym><v8:item><v8:lang>ru</v8:lang><v8:content>ФормаДокумента</v8:content></v8:item></Synonym><Comment/><FormType>Managed</FormType><IncludeHelpInContents>false</IncludeHelpInContents><UsePurposes><v8:Value xsi:type="app:ApplicationUsePurpose">PlatformApplication</v8:Value><v8:Value xsi:type="app:ApplicationUsePurpose">MobilePlatformApplication</v8:Value></UsePurposes></Properties></Form></MetaDataObject>