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/settings/GlobalSettingsSection.svelte

@@ -1,10 +1,10 @@
 <script lang="ts">
-	import type { UserSettingsStore, ThemeMode, WeekStartDay } from '@manacore/shared-theme';
-	import { getAvailableRoutes, getDefaultRoute } from '@manacore/shared-theme';
+	import type { UserSettingsStore, ThemeMode, WeekStartDay } from '@mana/shared-theme';
+	import { getAvailableRoutes, getDefaultRoute } from '@mana/shared-theme';
 	import SettingsSection from './SettingsSection.svelte';
 	import SettingsCard from './SettingsCard.svelte';
 	import NavVisibilitySettings from './NavVisibilitySettings.svelte';
-	import { Gear } from '@manacore/shared-icons';
+	import { Gear } from '@mana/shared-icons';
 
 	interface NavItem {
 		href: string;

packages/shared-ui/src/settings/NavVisibilitySettings.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-	import type { UserSettingsStore } from '@manacore/shared-theme';
+	import type { UserSettingsStore } from '@mana/shared-theme';
 	import {
 		House,
 		Users,
@@ -51,7 +51,7 @@
 		DownloadSimple,
 		Stack,
 		TrendUp,
-	} from '@manacore/shared-icons';
+	} from '@mana/shared-icons';
 
 	interface NavItem {
 		href: string;

packages/shared-ui/src/settings/SettingsRow.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import type { Snippet } from 'svelte';
-	import { CaretRight } from '@manacore/shared-icons';
+	import { CaretRight } from '@mana/shared-icons';
 
 	interface Props {
 		/** Row label */

packages/shared-ui/src/settings/SettingsTimeInput.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import type { Snippet } from 'svelte';
-	import { X } from '@manacore/shared-icons';
+	import { X } from '@mana/shared-icons';
 
 	interface Props {
 		/** Row label */