feat: enable updating time from a food entry

- Add visible time input (foodEntryTime) in index.html, hidden by default
- Show time input only when editing a food entry (setFoodToEdit)
- Use foodEntryTime value when saving an edited entry (updateFood)
- Hide and reset time input on clearEditing (cancel/save)
- input type=time ensures HH:MM format is preserved

Agent-Logs-Url: https://github.com/RMCampos/calories-tracker/sessions/085efbe7-b9c8-4a81-a58f-5dbdf91f2942

Co-authored-by: RMCampos <2219519+RMCampos@users.noreply.github.com>

index.html

@@ -267,6 +267,10 @@
                         <label for="gramAmount">Amount (grams)</label>
                         <input type="number" id="gramAmount" min="1" step="1" value="100">
                     </div>
+                    <div class="form-group hidden" id="foodTimeGroup">
+                        <label for="foodEntryTime">Time</label>
+                        <input type="time" id="foodEntryTime">
+                    </div>
                     <button class="add-btn" id="add-food-btn">Add Food</button>
                     <button class="cancel-btn" id="cancel-food-btn">Cancel</button>
                 </div>