Update admin theme/layout and refresh README details.

Align the project baseline with the latest admin interface styling and layout structure while documenting setup and usage updates in README.

apps/api/app/modules/content/service.py

@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+import bleach
+
+from app.modules.content import repository
+from app.modules.content.models import ContentPage
+
+ALLOWED_TAGS = ["p", "h1", "h2", "h3", "h4", "ul", "ol", "li", "a", "strong", "em", "br", "img"]
+
+
+def sanitize_html(raw_html: str) -> str:
+    return bleach.clean(
+        raw_html,
+        tags=ALLOWED_TAGS,
+        attributes={"a": ["href"], "img": ["src", "alt"]},
+        protocols=["http", "https", "mailto"],
+        strip=True,
+    )
+
+
+def page_to_dict(page: ContentPage) -> dict:
+    return {
+        "id": page.id,
+        "slug": page.slug,
+        "title": page.title,
+        "body": page.body,
+        "status": page.status,
+        "author_id": page.author_id,
+        "published_at": page.published_at.isoformat() if page.published_at else None,
+        "updated_at": page.updated_at.isoformat() if page.updated_at else None,
+    }
+
+
+def list_published_pages() -> list[ContentPage]:
+    return repository.list_published_pages()
+
+
+def list_all_pages() -> list[ContentPage]:
+    return repository.list_all_pages()
+
+
+def get_page_by_slug(slug: str, include_draft: bool = False) -> ContentPage | None:
+    return repository.get_page_by_slug(slug, include_draft=include_draft)
+
+
+def create_page(slug: str, title: str, body: str, status: str, author_id: str) -> ContentPage:
+    return repository.create_page(
+        slug=slug,
+        title=title,
+        body=sanitize_html(body),
+        status=status,
+        author_id=author_id,
+    )
+
+
+def update_page(page_id: str, title: str | None, body: str | None, status: str | None) -> ContentPage:
+    return repository.update_page(
+        page_id,
+        title,
+        sanitize_html(body) if body else None,
+        status,
+    )
+
+
+def delete_page(page_id: str) -> None:
+    repository.delete_page(page_id)
+
+
+def page_exists(page_id: str) -> bool:
+    return repository.get_page_by_id(page_id) is not None