feat(saas): extend agent templates with soul_content, add /available endpoint, key pool cleanup, and industry seed templates

- Add 9 extended fields to AgentTemplateInfo: soul_content, scenarios,
  welcome_message, quick_commands, personality, communication_style,
  emoji, version, source_id
- Refactor service.rs to use sqlx::Row (manual column extraction) to
  avoid the 16-element tuple FromRow limit
- Add /api/v1/agent-templates/available (lightweight public listing)
  and /api/v1/agent-templates/:id/full endpoints
- Add 24h key_usage_window cleanup task in scheduler
- Update seed data with extended fields for all 5 existing templates
  plus new Medical Assistant template (healthcare category)

crates/zclaw-saas/src/agent_template/mod.rs

@@ -11,7 +11,9 @@ use crate::state::AppState;
 pub fn routes() -> axum::Router<AppState> {
     axum::Router::new()
         .route("/api/v1/agent-templates", get(handlers::list_templates).post(handlers::create_template))
+        .route("/api/v1/agent-templates/available", get(handlers::list_available))
         .route("/api/v1/agent-templates/:id", get(handlers::get_template))
         .route("/api/v1/agent-templates/:id", post(handlers::update_template))
         .route("/api/v1/agent-templates/:id", delete(handlers::archive_template))
+        .route("/api/v1/agent-templates/:id/full", get(handlers::get_full_template))
 }