Add board timeline + per-card change log (who changed what and when) in Deck

Environment:

• Nextcloud: 32.0.1
• Deck: 1.16.2
• Client: Web UI (browser: brave
• DB: MySQL
• Install type: manual

Problem:
We use Deck with multiple users. Cards can be edited by several employees, but there is no reliable audit trail that shows who changed what and when. We need both:

1. a board-level timeline (overview of events)
2. a per-card change history (detailed)

Feature request / Expected behaviour:

A) Board timeline (overview)
Show a chronological timeline for the board including:

• card created / archived / restored / deleted
• card moved between stacks (from -> to)
• assignee changes
• due date changes
• label changes
• attachments added/removed
• comments added/edited (if supported)

B) Per-card change log (detail)
Inside each card, add an “Activity / History” view that records at least:

• title changes (old -> new)
• description changes
• checklist item add/edit/complete/uncomplete/delete
• due date changes
• assignees changes
• label changes
• attachments added/removed
• card moved (stack/position)
• archive/restore

Requirements:

• Show: user + timestamp + action + field (and previous/new value where meaningful)
• Ideally filter/search + export (JSON/CSV)
• Privacy: do not log full description text by default (log “description changed”; optional diff or previous value only behind a permission/setting)

Why:
Accountability, coordination in teams, and compliance/audit requirements.

Related issues:

• #1281 (History/timeline for a board)
• #1558 (Timeline and activity)
• #7201 (Visual diff-style output for card description changes)
• #7058 (Activity log with card description / avoid full text logging)

The issue names no files, tests, or entry points. Start by reviewing related issues #1281, #1558, #7201, and #7058 to understand existing discussion; done requires an agreed scope for board and card history, privacy behavior, and any filtering or export requirements.