feat: rename service to galo, add halo branding and release build

- rename Go module, binary, systemd unit, PG_DATABASE default, frontend package and docs from shared-album to galo
- add theme-aware halo emblem and favicon (new ui-branding capability)
- add make build-release (versioned, stripped, static binary) and run the binary from the repo root

frontend/src/lib/components/AppShell.svelte

@@ -2,6 +2,7 @@
 	import { onMount } from 'svelte';
 	import { goto } from '$app/navigation';
 	import { authApi } from '$lib/api';
+	import Emblem from './Emblem.svelte';
 	import Icon from './Icon.svelte';
 	import ThemeSwitcher from './ThemeSwitcher.svelte';
 	import { auth } from '$lib/stores/auth.svelte';
@@ -115,7 +116,7 @@
 				<Icon name="menu" class="size-4" />
 			</button>
 			<a href="/" class="inline-flex items-center gap-1.5 truncate text-sm font-semibold">
-				<Icon name="photo_camera" class="size-4" />
+				<Emblem class="text-primary size-4" />
 				Galo
 			</a>
 		</div>