[bug] File ownership incorrect after upload/ingest — prevents metadata edits, book deletion, and directory moves

[crocodilestick]

Summary

After uploading books via the web UI or importing via folder ingest, the resulting files and directories in /calibre-library have incorrect ownership. This prevents CWA from performing subsequent operations: editing metadata, deleting books, or moving directories during metadata updates.

Symptoms

• Manual upload ([bug] file permissions changed #1075): "rights are not recorded as USER, but as ROOT. The book cannot be edited or deleted."
• Folder ingest ([bug] Folder Ingest Results in Wrong Permissions in Version 4.0.6 #1287): Files owned by host UID/GID (e.g. 1000:1000) instead of the abc user, preventing CWA from managing them.
• Metadata edit after upload ([bug] Permission denied after modifying metadata of uploaded book #1241): Upload succeeds but editing metadata fails with:

  ERROR {cps.helper:626} Failed to move directory ... [Errno 13] Permission denied
  

Expected behavior

All files created in /calibre-library by CWA should be owned by the abc user so the application can manage them normally.

Environment

• CWA v4.0.6
• Affects both Docker and bare-metal installs
• Some reports are fresh installs where this is the first use

Related (consolidated from)

• [bug] file permissions changed #1075 — file permissions changed
• [bug] Folder Ingest Results in Wrong Permissions in Version 4.0.6 #1287 — Folder Ingest Results in Wrong Permissions in Version 4.0.6
• [bug] Permission denied after modifying metadata of uploaded book #1241 — Permission denied after modifying metadata of uploaded book