docs(node/Folder): update public interface docs

[joshtrichards]

Summary

Update public interface docs for OCP\Files\Folder to improve coverage, accuracy and clarity:

• how search() handles its two accepted query parameter forms
• tune the base descriptions getById() and getFirstNodeById() to more clearly separate and tidy overall descriptions
• slightly more specific description for getNonExistingName()
• add missing description for getRecent() including important details about non-empty folders and 2 week cut-off
• slightly more specific description for verifyPath()
• miscellaneous minor clarity/consistency improvements throughout
• drop unnecessary OCP class boilerplate

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