feat(database): add repairSmokeAIAdviceIndexes function and corresponding tests

- Implemented repairSmokeAIAdviceIndexes to manage the unique index for fa_smoke_ai_advice.
- Added unit tests for the new function to ensure correct index recreation and validation.
- Updated AutoMigrate to include the new index repair function.

internal/smoke/service/smoke_ai_model_test.go

@@ -0,0 +1,28 @@
+package service
+
+import "testing"
+
+func TestPreferredSmokeAIModel(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{name: "deepseek reasoner fallback", input: "deepseek-reasoner", want: "deepseek-chat"},
+		{name: "trim whitespace", input: " deepseek-reasoner ", want: "deepseek-chat"},
+		{name: "keep normal model", input: "gpt-4o-mini", want: "gpt-4o-mini"},
+		{name: "keep deepseek chat", input: "deepseek-chat", want: "deepseek-chat"},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			if got := preferredSmokeAIModel(tc.input); got != tc.want {
+				t.Fatalf("preferredSmokeAIModel(%q)=%q, want=%q", tc.input, got, tc.want)
+			}
+		})
+	}
+}