refactor(Template): clarify TemplateLayout naming, comments, and docblocks

[joshtrichards]

• Resolves: #

Summary

I'm working on some other changes in this class, but figured I'd submit these easier to review changes first.

This PR aims to improve readability of OC\TemplateLayout by clarifying naming, comments, and docblocks. It also adds basic unit test coverage.

Specific changes:

• Adds class docblock
• Adds key function docblocks
• Some minor code reformatting (lines 106-126)
• Renames variables for improved clarity
• Replaces vague comments
• Adds clarifying comments in key spots
• Makes locator properties private

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI