fix: RanobeLib parseNovel crash - summary field changed to rich-text doc

[Sma1lON]

Checklist

• Update version code if an existing plugin was modified
• Test changes in Plugin Playground or the app
• Reference related issues in the PR body (e.g. Closes #xyz)

The API now returns summary as a JSON doc object ({type:"doc",content:[...]})
instead of a plain string. Calling .trim() on the object threw
TypeError: data.summary.trim is not a function, crashing parseNovel entirely.

Fix by detecting the type: use .trim() for strings, jsonToHtml() for doc objects.
Also corrects the Branch.branch_id type from null to number|null.