Complete feedback system (enable existing commented-out feature)

[OlivierJM]

Feature Parity: Feedback System

Legacy app has a user feedback system. sparked-next has the admin feedback section commented out of the sidebar navigation — this issue is to complete and enable it.

Legacy capabilities

• Any authenticated user can submit feedback with title and description
• Feedback is attributed to the submitting user
• Feedback links back to the page it was submitted from
• Admins can view all submitted feedback (paginated)

Current state in sparked-next

Feedback admin section exists in codebase but is commented out of sidebar navigation.

Acceptance criteria

• POST /api/feedback — submit feedback (any authenticated user)
• GET /api/feedback — list feedback (admin only, paginated)
• User-facing feedback form (accessible from library/content pages)
• Admin feedback view page uncommented/enabled in navigation
• Feedback includes: title, description, source page URL, user attribution, timestamp

Identified via feature-parity audit against legacy Sparked (Meteor) app.