Store nutrition per serving, and check the estimate before sending it

Recipes imported from a video caption have no nutrition data, so the values
have to be estimated. Mealie will accept anything: the fields are free-text
strings, a misspelt key is dropped silently, and a whole-recipe total looks
exactly like a per-serving one. The recipe page then renders whatever landed
as fact.

patch_recipe now validates a nutrition block first. Keys must be Mealie's own,
so a number cannot vanish into "carbs". Values are normalized to bare numbers,
matching how the library already stores them. Energy is checked against the
macros with the Atwater factors (4/9/4 kcal per gram) and refused if it is
more than 25% off, which is what catches an arithmetic slip.

Nutrition is per serving, and the text import left recipeServings at 0 --- it
set only the free-text recipeYield, so "4-6 personer" gave Mealie no number to
divide by or scale with. import_recipe_text now also sets recipeServings, from
the lower bound of a range, which is how this library already stores
"10-12 personer" (recipeServings 10). patch_recipe refuses nutrition while the
count is still missing, and accepts it when the same patch supplies it.

verify_recipe fails an import that has no nutrition, or has values without a
serving count.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_verify.py

@@ -31,6 +31,9 @@ def complete_recipe(**overrides):
         "recipeCategory": [{"name": "Huvudrätter"}],
         "tags": [{"name": "Källa: Köket"}],
         "orgURL": "https://www.koket.se/kycklinggryta",
+        "recipeServings": 4,
+        "nutrition": {"calories": "520", "proteinContent": "31", "fatContent": "34",
+                      "carbohydrateContent": "18"},
     }
     recipe.update(overrides)
     return recipe
@@ -130,6 +133,22 @@ class TestTaxonomy:
         assert report["complete"] is True
 
 
+class TestNutrition:
+    def test_missing_nutrition_fails(self):
+        report = verify_recipe(complete_recipe(nutrition={}), image_verified=True)
+        assert status_of(report, "nutrition") == "fail"
+        assert report["complete"] is False
+
+    def test_values_without_a_serving_count_fail(self):
+        # Mealie shows nutrition per serving, so figures with recipeServings 0
+        # are a numerator without a denominator — the state the TikTok import left.
+        report = verify_recipe(complete_recipe(recipeServings=0), image_verified=True)
+        assert status_of(report, "nutrition") == "fail"
+        assert "recipeServings" in next(
+            c["detail"] for c in report["checks"] if c["check"] == "nutrition"
+        )
+
+
 class TestAttribution:
     def test_missing_source_warns_but_does_not_block(self):
         report = verify_recipe(