RecipeDeleteMultipleRecipesWithConstraint generates empty targets for mixed-case ingredients

## Summary

`RecipeDeleteMultipleRecipesWithConstraint` appears to build the target rows with a case-sensitive bug. The code lowercases each recipe's `directions`, but it does not lowercase the selected `ingredient`. When the selected ingredient is mixed-case, for example `Parmesan`, recipes whose directions contain `Parmesan cheese` are not selected as targets. They are instead treated as noise rows.

This can make the official target set empty (`row_objects: []`). The evaluator then checks that the empty target set was deleted, so an agent can delete nothing and still receive `success: 1.0`.

## Expected behavior

For a task with this goal:

```text
Delete the recipes from Broccoli app that use Parmesan in the directions.
```

any recipe whose `directions` contain `Parmesan` or `Parmesan cheese` should be included in `row_objects` and should have to be deleted for success.

## Actual behavior in the attached run

The retained evaluator input has:

```json
"ingredient": "Parmesan",
"row_objects": []
```

But the same `native_evaluator_input.json` includes multiple initialized recipe rows whose `directions` contain `Parmesan cheese`, for example:

- `Chicken Alfredo Pasta`: `Serve with a sprinkle of Parmesan cheese.`
- `Pesto Pasta with Peas`: `Add Parmesan cheese before serving.`
- `Chicken Caesar Salad Wrap`: `... grilled chicken strips, and Parmesan cheese.`
- another `Chicken Caesar Salad Wrap` variant with the same Parmesan-containing base direction.

The agent searched for `Parmesan`, opened two `Eggplant Parmesan` entries, decided their directions did not mention Parmesan, and ended without deleting any recipe. Despite that, the native evaluator output reports:

```json
"success": 1.0
```

## Likely root cause

In `RecipeDeleteMultipleRecipesWithConstraint.generate_random_params`, the filters compare `ingredient` against `r.directions.lower()`:

```python
filter_fn=lambda r: ingredient not in r.directions.lower()
...
filter_fn=lambda r: ingredient in r.directions.lower()
```

This is not a case-insensitive comparison unless `ingredient` is already lowercase. `_COMMON_INGREDIENTS` contains mixed-case values such as `Parmesan cheese` and `Parmesan`, so:

```python
"Parmesan" in "serve with a sprinkle of parmesan cheese"
```

is false.

As a result, real matching recipes are excluded from `row_objects`. In this run, the official evaluator checked deletion of an empty target set rather than checking the task's stated condition.

## Suggested fix

Normalize both sides of the comparison:

```python
ingredient_lower = ingredient.lower()

noise = sqlite_schema_utils.get_random_items(
cls.n_rows_noise,
_generate_random_recipe,
replacement=False,
filter_fn=lambda r: ingredient_lower not in r.directions.lower(),
)

targets = sqlite_schema_utils.get_random_items(
n_rows,
_generate_random_recipe,
replacement=False,
filter_fn=lambda r: ingredient_lower in r.directions.lower(),
)
```

It may also be worth rejecting or regenerating task instances where `row_objects` is empty, since this task class sets `n_rows = 3` and the user-facing goal implies there are recipes to delete.

## Files in the evidence package

- `evidence/native_evaluator_input.json`: shows `ingredient: "Parmesan"`, `row_objects: []`, and the Parmesan-containing noise rows.
- `evidence/native_evaluator_output.json`: shows `success: 1.0`.
- `evidence/trajectory_steps.json`: shows the agent searched/opened recipes and ended without deletion.
- `source/recipe.py`: local copy of the relevant AndroidWorld task source.
- `source/sqlite_validators.py`: local copy of the deletion validator used by the task.

[RecipeDeleteMultipleRecipesWithConstraint_agent_a_parmesan_issue.tar.gz](https://github.com/user-attachments/files/27901444/RecipeDeleteMultipleRecipesWithConstraint_agent_a_parmesan_issue.tar.gz)