Implement AI

API/ROLAC.API/Services/Ai/IExpenseAiService.cs

@@ -0,0 +1,14 @@
+using ROLAC.API.DTOs.Expense;
+
+namespace ROLAC.API.Services.Ai;
+
+/// <summary>AI assistance for expense entry: translate a description and suggest a category.</summary>
+public interface IExpenseAiService
+{
+    /// <summary>
+    /// Translate <paramref name="chineseText"/> to concise accounting English and suggest the best
+    /// major/sub category from the live catalog, using <paramref name="amount"/> as a hint.
+    /// Never throws on an upstream/AI failure — returns a suggestion with null fields instead.
+    /// </summary>
+    Task<ExpenseAiSuggestion> SuggestAsync(string chineseText, decimal amount, CancellationToken ct = default);
+}