fix(recipes): normalize newlines + add update_recipe (v0.6.1)

Bug fix: literal backslash-n sequences in ingredients/instructions are now
converted to real newline characters before sending to the API, so the server
correctly splits ingredient lines into ingredientsList[].

New tool: update_recipe — partial update via mprecipeput with recipe.metaId;
fetches current recipe in the same session to verify can_update and supply
name fallback. Verified: recipe.metaId triggers update (not create).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/mcp_familywall/server.py

@@ -13,6 +13,7 @@ from mcp_familywall.fw_client import FamilyWallClient, FamilyWallError
 from mcp_familywall.modules.lists import translate_name
 from mcp_familywall.modules.recipes import (
     build_create_params,
+    build_update_params,
     parse_recipe_full,
     parse_recipe_summary,
 )
@@ -1337,6 +1338,142 @@ def delete_recipe(recipe_id: str) -> str:
     )
 
 
+# ---------------------------------------------------------------------------
+# Tool: update_recipe
+# ---------------------------------------------------------------------------
+
+
+@mcp.tool()
+def update_recipe(
+    recipe_id: str,
+    name: str | None = None,
+    description: str | None = None,
+    ingredients: str | None = None,
+    instructions: str | None = None,
+    prep_time_minutes: int | None = None,
+    cook_time_minutes: int | None = None,
+    serves: int | None = None,
+    url: str | None = None,
+) -> str:
+    """Update an existing recipe in the Family Wall recipe box.
+
+    IMPORTANT: Ask the user for confirmation before calling this tool.
+
+    At least one field besides *recipe_id* must be provided.  Fields that are
+    omitted are left unchanged on the server.
+
+    Args:
+        recipe_id: Recipe metaId from get_recipes
+            (e.g. ``"recipe/23431854_10968866"``).
+        name: New recipe title (omit to keep existing).
+        description: New description (omit to keep existing).
+        ingredients: New ingredient list as free text (omit to keep existing).
+            Use newlines (``\\n``) to separate items.
+            Example: ``"200g Mehl\\n3 Eier\\n100ml Milch"``
+        instructions: New cooking instructions as free text (omit to keep
+            existing).  Use newlines (``\\n``) to separate steps.
+        prep_time_minutes: New preparation time in minutes (omit to keep
+            existing).
+        cook_time_minutes: New cooking/baking time in minutes (omit to keep
+            existing).
+        serves: New number of servings (omit to keep existing).
+        url: New external URL (omit to keep existing).
+
+    Returns:
+        JSON with the updated recipe's full fields on success, or an error
+        message.
+    """
+    if all(
+        v is None
+        for v in (
+            name,
+            description,
+            ingredients,
+            instructions,
+            prep_time_minutes,
+            cook_time_minutes,
+            serves,
+            url,
+        )
+    ):
+        return (
+            "Error: At least one of 'name', 'description', 'ingredients', 'instructions',"
+            " 'prep_time_minutes', 'cook_time_minutes', 'serves', or 'url' must be provided."
+        )
+
+    # Single session: fetch current recipe (verify + get name fallback) → update.
+    try:
+        email, password = get_credentials()
+    except RuntimeError as exc:
+        return f"Error: {exc}"
+
+    try:
+        with FamilyWallClient() as client:
+            client.login(email, password)
+
+            # Fetch all recipes to verify the target exists and is updatable.
+            raw_data = client.call("metasync", {"id": "recipe"})
+            try:
+                items: list[dict[str, Any]] = raw_data["a00"]["r"]["r"]["updatedCreated"]
+            except (KeyError, TypeError):
+                items = []
+
+            current = next((r for r in items if r.get("metaId") == recipe_id), None)
+            if current is None:
+                client.logout()
+                return f"Error: Recipe '{recipe_id}' not found."
+
+            can_update: str | None = (current.get("rights") or {}).get("canUpdate")
+            if can_update != "true":
+                client.logout()
+                return json.dumps(
+                    {
+                        "error": "Recipe cannot be updated.",
+                        "id": recipe_id,
+                        "name": current.get("name"),
+                        "hint": "Only recipes you created (can_update=true) can be updated.",
+                    },
+                    ensure_ascii=False,
+                    indent=2,
+                )
+
+            # Build params — current name is used as fallback when caller omits name.
+            params = build_update_params(
+                recipe_id=recipe_id,
+                current_name=current.get("name", ""),
+                name=name,
+                description=description,
+                ingredients=ingredients,
+                instructions=instructions,
+                prep_time_minutes=prep_time_minutes,
+                cook_time_minutes=cook_time_minutes,
+                serves=serves,
+                url=url,
+            )
+
+            resp = client.call("mprecipeput", params)
+            client.logout()
+    except FamilyWallError as exc:
+        return f"Error: Family Wall API error: {exc}"
+    except Exception as exc:
+        return f"Error: Connection error: {exc}"
+
+    try:
+        recipe_obj = resp["a00"]["r"]["r"]
+        if not isinstance(recipe_obj, dict) or "metaId" not in recipe_obj:
+            raise TypeError("unexpected shape")
+    except (KeyError, TypeError):
+        return json.dumps(
+            {"warning": "Unexpected mprecipeput response structure", "raw": resp},
+            ensure_ascii=False,
+            indent=2,
+        )
+
+    result = parse_recipe_full(recipe_obj)
+    result["updated"] = True
+    return json.dumps(result, ensure_ascii=False, indent=2)
+
+
 # ---------------------------------------------------------------------------
 # Factory
 # ---------------------------------------------------------------------------