✨ feat: implement mock data support with API interceptor and update documentation

frontend/mocking/content.json

@@ -0,0 +1,76 @@
+[
+    {
+        "id": "home",
+        "_id": "home",
+        "active": true,
+        "type": "page",
+        "lang": "de",
+        "translationKey": "home",
+        "name": "Startseite",
+        "path": "/",
+        "blocks": [
+            {
+                "type": "hero",
+                "headline": "Willkommen",
+                "headlineH1": true,
+                "subline": "Demo-Startseite des Starter-Templates",
+                "heroImage": {
+                    "image": "demo-hero"
+                }
+            },
+            {
+                "type": "richtext",
+                "headline": "Über uns",
+                "text": "<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>"
+            }
+        ],
+        "meta": {
+            "title": "Startseite",
+            "description": "Demo-Startseite"
+        }
+    },
+    {
+        "id": "about",
+        "_id": "about",
+        "active": true,
+        "type": "page",
+        "lang": "de",
+        "translationKey": "about",
+        "name": "Über uns",
+        "path": "/ueber-uns",
+        "blocks": [
+            {
+                "type": "richtext",
+                "headline": "Über uns",
+                "headlineH1": true,
+                "text": "<p>Wir sind ein Demo-Unternehmen.</p>"
+            }
+        ],
+        "meta": {
+            "title": "Über uns",
+            "description": "Erfahren Sie mehr über uns"
+        }
+    },
+    {
+        "id": "contact",
+        "_id": "contact",
+        "active": true,
+        "type": "page",
+        "lang": "de",
+        "translationKey": "contact",
+        "name": "Kontakt",
+        "path": "/kontakt",
+        "blocks": [
+            {
+                "type": "richtext",
+                "headline": "Kontakt",
+                "headlineH1": true,
+                "text": "<p>Schreiben Sie uns eine Nachricht.</p>"
+            }
+        ],
+        "meta": {
+            "title": "Kontakt",
+            "description": "Kontaktieren Sie uns"
+        }
+    }
+]

frontend/mocking/navigation.json

@@ -0,0 +1,38 @@
+[
+    {
+        "id": "header-de",
+        "_id": "header-de",
+        "language": "de",
+        "type": "header",
+        "elements": [
+            {
+                "name": "Startseite",
+                "page": "home"
+            },
+            {
+                "name": "Über uns",
+                "page": "about"
+            },
+            {
+                "name": "Kontakt",
+                "page": "contact"
+            }
+        ]
+    },
+    {
+        "id": "footer-de",
+        "_id": "footer-de",
+        "language": "de",
+        "type": "footer",
+        "elements": [
+            {
+                "name": "Impressum",
+                "page": "imprint"
+            },
+            {
+                "name": "Datenschutz",
+                "page": "privacy"
+            }
+        ]
+    }
+]