Sanitize markdown output in edit history and TOC edit views

[djmb]

The edit history view and TOC edit partial render Markdown content via to_html without passing through sanitize_content(), unlike the normal page view. This allows stored XSS via img onerror payloads for anyone who can view the edit history of a page with injected content.

Apply sanitize_content() consistently to all to_html output, matching the existing safe pattern in leafables/show.html.erb.

[Copilot]

Pull request overview

This PR hardens page rendering against XSS by sanitizing HTML output for page bodies, including in the edit history view and page thumbnails, and adds regression tests to verify dangerous attributes are stripped.

Changes:

• Sanitize rendered HTML for both “previous version” and “current” page bodies in the page edit history view.
• Sanitize rendered HTML for page thumbnails in the leaves edit partial.
• Add controller/integration tests ensuring dangerous attributes (e.g., onerror) are removed from rendered output.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
app/views/pages/edits/show.html.erb	Sanitizes HTML output for both the selected edit’s page body and the current page body.
app/views/leaves/_edit.html.erb	Sanitizes page-body HTML used in the leaf thumbnail preview.
test/controllers/pages/edits_controller_test.rb	Adds tests covering sanitization for previous and current versions.

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