feat: startup git clone for template repo + pass config through

- ensure_repo_ready() at startup: clone if missing, fetch if exists
- TemplateRepoConfig gains local_path field
- list_all_templates/select_template/extract_repo_template accept repo config
- Remove hardcoded repo_dir(), use config.local_path

src/api/workflows.rs

@@ -197,6 +197,8 @@ async fn list_llm_calls(
     .map_err(db_err)
 }
 
-async fn list_templates() -> Json<Vec<template::TemplateListItem>> {
-    Json(template::list_all_templates().await)
+async fn list_templates(
+    State(state): State<Arc<AppState>>,
+) -> Json<Vec<template::TemplateListItem>> {
+    Json(template::list_all_templates(state.config.template_repo.as_ref()).await)
 }