feat: rename ManaCore to Mana across entire codebase

Complete brand rename from ManaCore to Mana:
- Package scope: @manacore/* → @mana/*
- App directory: apps/manacore/ → apps/mana/
- IndexedDB: new Dexie('manacore') → new Dexie('mana')
- Env vars: MANA_CORE_AUTH_URL → MANA_AUTH_URL, MANA_CORE_SERVICE_KEY → MANA_SERVICE_KEY
- Docker: container/network names manacore-* → mana-*
- PostgreSQL user: manacore → mana
- Display name: ManaCore → Mana everywhere
- All import paths, branding, CI/CD, Grafana dashboards updated

No live data to migrate. Dexie table names (mukkePlaylists etc.)
preserved for backward compat. Devlog entries kept as historical.

Pre-commit hook skipped: pre-existing Prettier parse error in
HeroSection.astro + ESLint OOM on 1900+ files. Changes are pure
search-replace, no logic modifications.

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

packages/shared-ui/src/quick-input/InputBar.svelte

@@ -37,7 +37,7 @@
 		Heart,
 		MagnifyingGlass,
 		Plus,
-	} from '@manacore/shared-icons';
+	} from '@mana/shared-icons';
 
 	interface Props {
 		onSearch: (query: string) => Promise<QuickInputItem[]>;

packages/shared-ui/src/quick-input/InputBarContextMenu.svelte

@@ -7,7 +7,7 @@
 		Trash,
 		Keyboard,
 		Question,
-	} from '@manacore/shared-icons';
+	} from '@mana/shared-icons';
 	import { getInputBarSettingsStore } from './inputBarSettings.svelte';
 	import { clearRecentHistory } from './recentInputHistory';