feat: add compose and decompose numbers problem

app/problems/grade_1/compose_and_decompose_numbers.py

@@ -0,0 +1,42 @@
+import random
+
+from app.schemas.grade_1.compose_and_decompose_numbers import (
+    ComposeAndDecomposeNumbersProblem,
+    DecompositionRow,
+    PictureAsset,
+)
+
+
+def compose_and_decompose_numbers(
+    picture: dict,
+    whole: int = 10,
+    randomize_rows: bool = False,
+    seed: int | None = None,
+) -> dict:
+    """Generate number decomposition rows for one picture asset."""
+    if whole < 2:
+        raise ValueError("whole must be at least 2")
+
+    selected_picture = PictureAsset.model_validate(picture)
+    pairs = [(first_part, whole - first_part) for first_part in range(whole - 1, 0, -1)]
+
+    if randomize_rows:
+        rng = random.Random(seed)
+        rng.shuffle(pairs)
+
+    problem = ComposeAndDecomposeNumbersProblem(
+        whole=whole,
+        picture=selected_picture,
+        rows=[
+            DecompositionRow(
+                position=index + 1,
+                whole=whole,
+                first_part=first_part,
+                second_part=second_part,
+                picture=selected_picture,
+            )
+            for index, (first_part, second_part) in enumerate(pairs)
+        ],
+    )
+
+    return problem.model_dump()