feat(cms): add rich content to MediaCollectionItem

[Ur-imazing]

Epic: #120

Add to media-collection-item component:

• descriptionOverride (text, optional)
• repeatable relatedQuestions (e.g. strings or small component)
• repeatable bibleQuotes (quote + attribution)
• repeatable relatedResources (label + link)

Enables Easter-style featured/player blocks with description, questions, quotes, and resource links per item.

[Ur-imazing]

Closing as outdated; parent epic #120 is being retired.