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>

packages/shared-tailwind/src/themes.css

@@ -26,7 +26,7 @@
  *   3. NEVER write raw `var(--color-X)` without wrapping with `hsl()`.
  *      The variable holds raw channels, not a valid CSS color. A bare
  *      `color: var(--color-foreground)` is NOT an error — the browser
- *      silently falls back to `inherit`, which is how the early P5 zitare
+ *      silently falls back to `inherit`, which is how the early P5 quotes
  *      regression produced white-on-white text in light mode. Always wrap.
  *
  *      ❌  color: var(--color-foreground);