Add i18n support and integrate localized strings across modules (Login, AppShell, etc.)

finlog_app/app/assets/i18n/en.i18n.json

@@ -1,8 +1,30 @@
 {
   "hello": "Hello $name",
   "login": {
+    "title": "Login",
+    "pleaseSignIn": "Please sign in",
+    "signingIn": "Signing you in…",
     "success": "Logged in successfully"
   },
+  "dashboard": {
+    "welcome": "Dashboard – Welcome to Finlog"
+  },
+  "budget": {
+    "title": "Budgets"
+  },
+  "app": {
+    "navigationSettings": "Settings",
+    "navigationDashboard": "Dashboard",
+    "navigationBudgets": "Budgets",
+    "navigationInventory": "Inventory",
+    "navigationReports": "Reports",
+    "tooltipMenu": "Menu",
+    "tooltipNotifications": "Notifications",
+    "tooltipUserSettings": "User Settings",
+    "tooltipCollapseRail": "Collapse Rail",
+    "tooltipExpandRail": "Expand Rail",
+    "drawerSettings": "Settings"
+  },
   "settings": {
     "title": "Settings",
     "sections": {
@@ -21,6 +43,38 @@
     },
     "messages": {
       "logoutNotImplemented": "Logout… (not implemented yet)"
+    },
+    "app": {
+      "systemBackground": "System Background Color",
+      "systemDefault": "System Default",
+      "darkMode": "Dark Mode",
+      "lightMode": "Light Mode",
+      "textSize": "Text Size",
+      "system": "System",
+      "small": "Small",
+      "medium": "Medium",
+      "large": "Large",
+      "language": "Language",
+      "german": "German",
+      "english": "English"
+    },
+    "personalData": {
+      "name": "Name",
+      "maxMustermann": "Max Mustermann",
+      "changePassword": "Change Password",
+      "twoFactor": "Two-Factor Authentication",
+      "off": "Off"
+    },
+    "accountManagement": {
+      "email": "Email"
+    },
+    "help": {
+      "faq": "FAQ",
+      "sendFeedback": "Send Feedback"
+    },
+    "legal": {
+      "privacy": "Privacy",
+      "termsOfService": "Terms of Service"
     }
   }
 }