refactor: rename ManaDeck to Cards across entire monorepo

Rename the flashcard/deck management app from ManaDeck to Cards:
- Directory: apps/manadeck → apps/cards, packages/manadeck-database → packages/cards-database
- Packages: @manadeck/* → @cards/*, @manacore/manadeck-database → @manacore/cards-database
- Domain: manadeck.mana.how → cards.mana.how
- Storage: manadeck-storage → cards-storage
- Database: manadeck → cards
- All shared packages, infra configs, services, i18n, and docs updated
- 244 files changed, zero remaining manadeck references

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-links/src/deep-links.ts

@@ -42,7 +42,7 @@ const DEEP_LINK_PATTERNS: Record<string, Record<string, string>> = {
 		documents: '/documents/{id}',
 		spaces: '/spaces/{id}',
 	},
-	manadeck: {
+	cards: {
 		decks: '/decks/{id}',
 		cards: '/decks/{id}', // Navigate to deck containing the card
 	},