feat(a11y): fix logo link accessible name to include 'Vikunja'

Changes aria-label from 'Overview' to 'Vikunja home' so the
accessible name includes the visible text.

Fixes WCAG 2.5.3 (Label in Name).

frontend/src/components/home/AppHeader.vue

@@ -7,7 +7,7 @@
 		<RouterLink
 			:to="{ name: 'home' }"
 			class="logo-link"
-			:aria-label="$t('navigation.overview')"
+			:aria-label="$t('navigation.home')"
 		>
 			<Logo
 				width="164"

frontend/src/components/home/Navigation.vue

@@ -8,7 +8,7 @@
 			<RouterLink
 				:to="{name: 'home'}"
 				class="logo"
-				:aria-label="$t('navigation.overview')"
+				:aria-label="$t('navigation.home')"
 			>
 				<Logo
 					width="164"