refactor: rename zitare -> quotes (Zitate)

Zitare was opaque Latin/Italian-flavored branding. Renamed to clear
English "quotes" (DE: Zitate) matching short-concrete-noun cluster.

- Module, routes, API, i18n, standalone landing app, plans dirs
- Dexie tables: quotesFavorites, quotesLists, quotesListTags,
  customQuotes (dropped redundant "quotes" prefix on the last)
- Logo QuotesLogo, theme quotes.css, search provider, dashboard
  widget QuoteWidget
- German user-facing label "Zitate" (English brand stays Quotes)

Pre-launch, no data migration needed.

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

docker/prometheus/prometheus.yml

@@ -229,7 +229,7 @@ scrape_configs:
           - https://mana.how/food
           - https://mana.how/plants
           - https://mana.how/calc
-          - https://mana.how/zitare
+          - https://mana.how/quotes
           - https://mana.how/cards
           - https://mana.how/skilltree
           - https://mana.how/music