i18n: translate page titles (home, persons, admin, login, error)

Replaces hardcoded German strings with Paraglide message keys
(page_title_home/persons/admin/login/error) across de/en/es.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/messages/de.json

@@ -307,5 +307,10 @@
 	"notification_prefs_no_email": "Bitte trage zuerst eine E-Mail-Adresse ein, um Benachrichtigungen zu erhalten.",
 	"notification_unread": "ungelesen",
 	"mention_btn_label": "Person erwähnen",
-	"mention_popup_empty": "Keine Nutzer gefunden"
+	"mention_popup_empty": "Keine Nutzer gefunden",
+	"page_title_home": "Archiv",
+	"page_title_persons": "Personen",
+	"page_title_admin": "Administration",
+	"page_title_login": "Anmelden",
+	"page_title_error": "Fehler – Familienarchiv"
 }

frontend/messages/en.json

@@ -307,5 +307,10 @@
 	"notification_prefs_no_email": "Please add an email address above to receive notifications.",
 	"notification_unread": "unread",
 	"mention_btn_label": "Mention person",
-	"mention_popup_empty": "No users found"
+	"mention_popup_empty": "No users found",
+	"page_title_home": "Archive",
+	"page_title_persons": "Persons",
+	"page_title_admin": "Administration",
+	"page_title_login": "Sign in",
+	"page_title_error": "Error – Family Archive"
 }

frontend/messages/es.json

@@ -307,5 +307,10 @@
 	"notification_prefs_no_email": "Por favor, añade una dirección de correo electrónico para recibir notificaciones.",
 	"notification_unread": "no leído",
 	"mention_btn_label": "Mencionar persona",
-	"mention_popup_empty": "No se encontraron usuarios"
+	"mention_popup_empty": "No se encontraron usuarios",
+	"page_title_home": "Archivo",
+	"page_title_persons": "Personas",
+	"page_title_admin": "Administración",
+	"page_title_login": "Iniciar sesión",
+	"page_title_error": "Error – Archivo familiar"
 }

frontend/src/routes/+error.svelte

@@ -1,9 +1,10 @@
 <script lang="ts">
 import { page } from '$app/state';
+import { m } from '$lib/paraglide/messages.js';
 </script>
 
 <svelte:head>
-	<title>Fehler – Familienarchiv</title>
+	<title>{m.page_title_error()}</title>
 </svelte:head>
 
 <div class="px-4 py-12 text-center font-sans">

frontend/src/routes/+page.svelte

@@ -68,7 +68,7 @@ $effect(() => {
 </script>
 
 <svelte:head>
-	<title>Archiv</title>
+	<title>{m.page_title_home()}</title>
 </svelte:head>
 
 <main class="mx-auto max-w-7xl px-4 py-8 font-sans sm:px-6 lg:px-8">

frontend/src/routes/admin/+page.svelte

@@ -12,7 +12,7 @@ let activeTab = $state('users');
 </script>
 
 <svelte:head>
-	<title>Administration</title>
+	<title>{m.page_title_admin()}</title>
 </svelte:head>
 
 <div class="mx-auto max-w-7xl px-4 py-8 font-sans sm:px-6 lg:px-8">

frontend/src/routes/login/+page.svelte

@@ -10,7 +10,7 @@ const activeLocale = $derived(getLocale().toUpperCase());
 </script>
 
 <svelte:head>
-	<title>Anmelden</title>
+	<title>{m.page_title_login()}</title>
 </svelte:head>
 
 <div class="relative flex min-h-screen flex-col bg-canvas">

frontend/src/routes/persons/+page.svelte

@@ -24,7 +24,7 @@ function handleSearch() {
 </script>
 
 <svelte:head>
-	<title>Personen</title>
+	<title>{m.page_title_persons()}</title>
 </svelte:head>
 
 <div class="mx-auto max-w-7xl px-4 py-12 sm:px-6 lg:px-8">