feat(shared): add DevBuildBadge component and getBuildDefines() helper

- shared-vite-config: getBuildDefines() injects __BUILD_HASH__ and
  __BUILD_TIME__ as compile-time constants via Vite define
- shared-ui: DevBuildBadge component shows git hash + build timestamp
  in a small fixed badge at bottom-right (click to expand)
- Integrated into mukke-web for deployment verification

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

apps/mukke/apps/web/src/app.d.ts

@@ -0,0 +1,2 @@
+declare const __BUILD_HASH__: string;
+declare const __BUILD_TIME__: string;

apps/mukke/apps/web/src/routes/(app)/+layout.svelte

@@ -2,7 +2,7 @@
 	import { goto } from '$app/navigation';
 	import { page } from '$app/stores';
 	import { onMount } from 'svelte';
-	import { PillNavigation } from '@manacore/shared-ui';
+	import { PillNavigation, DevBuildBadge } from '@manacore/shared-ui';
 	import type { PillNavItem, PillDropdownItem } from '@manacore/shared-ui';
 	import {
 		SplitPaneContainer,
@@ -166,6 +166,7 @@
 			<MiniPlayer />
 			<FullPlayer />
 			<QueuePanel />
+			<DevBuildBadge commitHash={__BUILD_HASH__} buildTime={__BUILD_TIME__} />
 		</div>
 	</SplitPaneContainer>
 {/if}

apps/mukke/apps/web/vite.config.ts

@@ -3,7 +3,7 @@ import { defineConfig } from 'vite';
 import tailwindcss from '@tailwindcss/vite';
 import { SvelteKitPWA } from '@vite-pwa/sveltekit';
 import { createPWAConfig } from '@manacore/shared-pwa';
-import { MANACORE_SHARED_PACKAGES } from '@manacore/shared-vite-config';
+import { MANACORE_SHARED_PACKAGES, getBuildDefines } from '@manacore/shared-vite-config';
 
 export default defineConfig({
 	plugins: [
@@ -28,4 +28,7 @@ export default defineConfig({
 	optimizeDeps: {
 		exclude: [...MANACORE_SHARED_PACKAGES, '@mukke/shared'],
 	},
+	define: {
+		...getBuildDefines(),
+	},
 });