perf: index workflow route model lookup

migrations/20260629000001_workflow_route_model_index.sql

@@ -0,0 +1,4 @@
+CREATE INDEX IF NOT EXISTS token_routes_enabled_model_pattern_nocase_idx
+    ON token_routes (COALESCE(enabled, 1), model_pattern COLLATE NOCASE)
+    WHERE model_pattern IS NOT NULL
+      AND model_pattern <> '';

src/routes/workflow_ui/models.rs

@@ -119,7 +119,7 @@ pub(super) fn is_chat_workflow_model(value: &str) -> bool {
 
 pub(super) async fn workflow_route_models(state: &AppState) -> AppResult<Vec<String>> {
     let rows = sqlx::query_scalar::<_, String>(
-        "SELECT DISTINCT model_pattern
+        "SELECT model_pattern
          FROM token_routes
          WHERE COALESCE(enabled, 1) = 1
            AND model_pattern IS NOT NULL