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/core/dependencies.py

@@ -0,0 +1,38 @@
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+
+from app.core.security import decode_access_token
+from app.modules.users.repository import get_user_by_id
+
+bearer = HTTPBearer(auto_error=False)
+
+
+def get_current_user(credentials: HTTPAuthorizationCredentials | None = Depends(bearer)):
+    if credentials is None:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="UNAUTHORIZED")
+    try:
+        payload = decode_access_token(credentials.credentials)
+    except Exception as exc:  # pragma: no cover - defensive
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="INVALID_TOKEN") from exc
+    user = get_user_by_id(payload["sub"])
+    if not user:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="UNAUTHORIZED")
+    if user.status == "pending":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="EMAIL_NOT_VERIFIED")
+    if user.status == "blocked":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="ACCOUNT_BLOCKED")
+    return user
+
+
+def require_admin(user=Depends(get_current_user)):
+    if user.role != "admin":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="ADMIN_ONLY")
+    return user
+
+
+def require_superuser(user=Depends(get_current_user)):
+    if user.role != "admin":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="ADMIN_ONLY")
+    if not user.is_superuser:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="SUPERUSER_ONLY")
+    return user