feat: custom board templates (#98) (#209)

* feat: add type and sourceId columns to board schema

* chore: update _journal and add snapshot

* feat: scaffold templates page

* feat: add template pages

* feat: add template card page

* feat: add template view indicator

* fix: ensure checklists default to empty array in board view

* feat: create template from board

* feat: show custom templates in new board form

* feat: create card activity from snapshot creation

* chore: update readme and features

* chore: add translations

README.md

@@ -27,7 +27,7 @@
 - 🔍 **Labels & Filters**: Organise and find cards quickly
 - 💬 **Comments**: Discuss and collaborate with your team
 - 📝 **Activity Log**: Track all card changes with detailed activity history
-- 🎨 **Templates (coming soon)** : Save time with reusable board templates
+- 🎨 **Templates** : Save time with reusable custom board templates
 - ⚡️ **Integrations (coming soon)** : Connect your favourite tools
 
 See our [roadmap](https://kan.bn/kan/roadmap) for upcoming features.