[dklawren]

Review carried over from private pull request
https://bugzilla.mozilla.org/show_bug.cgi?id=2081090

[Copilot]

🟢 Approval recommended

The narrowly scoped normalization has focused regression coverage and no identified blocking issues.

No open issues 🎉

What changed in this PR

This PR addresses Bug 2081090 by normalizing content-type extensions in get_format, keeping template selection, content-type lookup, and callers’ extension checks consistent.

Changes:

• Lowercase ctype before constructing the template filename.
• Add regression tests for mixed-case inputs, the default HTML extension, and the unknown content-type fallback.

File	Description
t/​template-get-format-case.t	Tests case normalization, default behavior, and fallback content type.
Bugzilla/​Template.pm	Normalizes ctype to lowercase before template resolution.

_{Review effort: Balanced}