feat(openclaw): add agents.defaults config support

- Add types for default model config (primary + fallbacks)
- Add types for model catalog/allowlist with aliases
- Extend OpenClawModelEntry with cost and contextWindow fields
- Add Tauri commands: get/set_openclaw_default_model, get/set_openclaw_model_catalog
- Create frontend API (src/lib/api/openclaw.ts)
- Add suggestedDefaults to provider presets with model metadata
- Add i18n translations (zh/en/ja) for openclawConfig.*

src-tauri/src/lib.rs

@@ -1007,6 +1007,10 @@ pub fn run() {
             // OpenClaw specific
             commands::import_openclaw_providers_from_live,
             commands::get_openclaw_live_provider_ids,
+            commands::get_openclaw_default_model,
+            commands::set_openclaw_default_model,
+            commands::get_openclaw_model_catalog,
+            commands::set_openclaw_model_catalog,
             // Global upstream proxy
             commands::get_global_proxy_url,
             commands::set_global_proxy_url,