feat(saas): 接通 embedding 模型管理全栈

数据库 migration 已有 is_embedding/model_type 列但全栈未使用。
打通 4 层: ModelRow → ModelInfo/CRUD → CachedModel → Admin 前端。
relay/models 端点也返回 is_embedding 字段，前端可按类型过滤。

crates/zclaw-saas/src/cache.rs

@@ -21,6 +21,8 @@ pub struct CachedModel {
     pub supports_streaming: bool,
     pub supports_vision: bool,
     pub enabled: bool,
+    pub is_embedding: bool,
+    pub model_type: String,
     pub pricing_input: f64,
     pub pricing_output: f64,
 }
@@ -111,15 +113,15 @@ impl AppCache {
         self.providers.retain(|k, _| provider_keys.contains(k));
 
         // Load models (key = model_id for relay lookup) — insert-then-retain
-        let model_rows: Vec<(String, String, String, String, i64, i64, bool, bool, bool, f64, f64)> = sqlx::query_as(
+        let model_rows: Vec<(String, String, String, String, i64, i64, bool, bool, bool, bool, String, f64, f64)> = sqlx::query_as(
             "SELECT id, provider_id, model_id, alias, context_window, max_output_tokens,
-                    supports_streaming, supports_vision, enabled, pricing_input, pricing_output
+                    supports_streaming, supports_vision, enabled, is_embedding, model_type, pricing_input, pricing_output
              FROM models"
         ).fetch_all(db).await?;
 
         let model_keys: HashSet<String> = model_rows.iter().map(|(_, _, mid, ..)| mid.clone()).collect();
         for (id, provider_id, model_id, alias, context_window, max_output_tokens,
-             supports_streaming, supports_vision, enabled, pricing_input, pricing_output) in &model_rows
+             supports_streaming, supports_vision, enabled, is_embedding, model_type, pricing_input, pricing_output) in &model_rows
         {
             self.models.insert(model_id.clone(), CachedModel {
                 id: id.clone(),
@@ -131,6 +133,8 @@ impl AppCache {
                 supports_streaming: *supports_streaming,
                 supports_vision: *supports_vision,
                 enabled: *enabled,
+                is_embedding: *is_embedding,
+                model_type: model_type.clone(),
                 pricing_input: *pricing_input,
                 pricing_output: *pricing_output,
             });