fix: resolve internal content urls by path, not by string

A backup holding a PDF attachment could not be imported back: legacy links
carry a cache-buster (".../files/m1/doc.pdf?v=1783170649"), and the resolver
compared the raw tail with its sanitized form, so the query made the name
differ from itself. The reference then read as internal by prefix and
non-canonical by name, which is exactly the combination _content_state must
refuse — every such document failed with invalid_content.

Parse the url as a url: the path addresses the file, the query and the
fragment address the transfer. Path segments keep doing the guarding, so
dropping the query cannot widen what a segment is allowed to be.

Issue: #225
User-Visible: yes

docs/CHANGELOG.md

@@ -7,6 +7,11 @@
   contains only the remaining active visible entities and disappears when
   none remain; two explicitly placed entity/device markers still coexist
   ([#226](https://github.com/Matysh/houseplan-card/issues/226)).
+- Fixed a backup with PDF attachments refusing to import back with "The backup
+  contains invalid or inconsistent content references". Attachment links that
+  carry a cache-buster (`…/files/marker/doc.pdf?v=1783170649`) are now resolved
+  by their path, as a URL rather than as a string
+  ([#225](https://github.com/Matysh/houseplan-card/issues/225)).
 
 ## v1.66.0 — 2026-08-20
 

docs/CHANGELOG.ru.md

@@ -14,6 +14,11 @@
   пустом остатке он исчезает; две явно размещённые привязки entity/device
   по-прежнему могут сосуществовать
   ([#226](https://github.com/Matysh/houseplan-card/issues/226)).
+- Исправлено: резервная копия с прикреплёнными PDF отказывалась импортироваться
+  обратно с сообщением «Резервная копия содержит некорректные или
+  несогласованные ссылки на файлы». Ссылки на вложения с кэш-бастером
+  (`…/files/маркер/doc.pdf?v=1783170649`) теперь разбираются по пути — как URL,
+  а не как строка ([#225](https://github.com/Matysh/houseplan-card/issues/225)).
 
 ## v1.66.0 — 2026-08-20