feat(proxy): WorkBuddyModelProvider 增加 supports 判断

供聚合路由按模型匹配 WorkBuddy 供应商。

app/src/main/java/com/rainy/token/data/proxy/WorkBuddyModelProvider.kt

@@ -52,6 +52,13 @@ class WorkBuddyModelProvider @Inject constructor(
         prefs.edit().putString(key, id).apply()
     }
 
+    /** 该区域是否可能支持此模型（在线/内置列表）。 */
+    fun supports(modelId: String, region: ProviderRegion): Boolean {
+        val want = modelId.trim().lowercase()
+        if (want.isBlank() || want == "auto") return true
+        return models.value.any { it.id.equals(modelId, ignoreCase = true) }
+    }
+
     suspend fun refreshFor(region: ProviderRegion): Boolean = withContext(Dispatchers.IO) {
         val credential = credentialRepository.get(ServiceType.WORKBUDDY, null)
             ?: return@withContext false