feat(settings): clarify custom gateway format

app/gui/tabs/settings.py

@@ -67,7 +67,10 @@ class SettingsTab(QWidget):
 
     settingsSaved = Signal(str)
 
-    BACKEND_ITEMS = [("默认网关", "cmhub"), ("自定义网关", "direct")]
+    BACKEND_ITEMS = [
+        ("默认网关", "cmhub"),
+        ("自定义网关（仅支持 OpenAI 格式）", "direct"),
+    ]
     CATEGORY_ITEMS = [("文本", "text"), ("图像", "image")]
     API_TYPE_ITEMS = [("chat", "chat"), ("images_edits", "images_edits"), ("auto", "auto")]
     IMAGE_API_TYPE_ITEMS = [("OpenAI 图片编辑接口", "images_edits")]
@@ -118,8 +121,11 @@ class SettingsTab(QWidget):
         self.backend_combo.setVisible(False)
         self.gateway_default_button = QRadioButton("默认网关")
         self.gateway_default_button.setObjectName("gatewayDefaultButton")
-        self.gateway_custom_button = QRadioButton("自定义网关")
+        self.gateway_custom_button = QRadioButton("自定义网关（仅支持 OpenAI 格式）")
         self.gateway_custom_button.setObjectName("gatewayCustomButton")
+        self.gateway_custom_button.setToolTip(
+            "仅支持 OpenAI 格式的文本接口和图片编辑接口。"
+        )
         self.gateway_button_group = QButtonGroup(self)
         self.gateway_button_group.setExclusive(True)
         self.gateway_button_group.addButton(self.gateway_default_button)
@@ -138,6 +144,13 @@ class SettingsTab(QWidget):
             "QRadioButton:focus { border: 1px solid #0969da; border-radius: 4px; }"
             "QRadioButton::indicator { width: 15px; height: 15px; }"
         )
+        self.custom_gateway_hint_label = QLabel(
+            "只有服务商明确说明“支持 OpenAI 格式接口”时才选择此项。"
+        )
+        self.custom_gateway_hint_label.setObjectName("customGatewayFormatHintLabel")
+        self.custom_gateway_hint_label.setStyleSheet("color: #57606a; padding: 0 12px;")
+        self.custom_gateway_hint_label.setWordWrap(True)
+        self.custom_gateway_hint_label.setVisible(False)
         self.cmhub_base_url_edit = QLineEdit()
         self.cmhub_base_url_edit.setObjectName("cmhubBaseUrlEdit")
         self.cmhub_base_url_edit.setPlaceholderText("https://host（不要带 /api 或 /api/v1）")
@@ -419,6 +432,7 @@ class SettingsTab(QWidget):
         )
         panel_layout.addWidget(self.ai_model_section_title)
         panel_layout.addWidget(self.gateway_selector)
+        panel_layout.addWidget(self.custom_gateway_hint_label)
         panel_layout.addSpacing(8)
         panel_layout.addWidget(self.model_picker_panel)
         panel_layout.addSpacing(8)
@@ -674,6 +688,7 @@ class SettingsTab(QWidget):
         self.backend_combo.blockSignals(previous)
         self.backend_combo.setVisible(False)
         is_direct = backend == "direct"
+        self.custom_gateway_hint_label.setVisible(is_direct)
         self.model_picker_panel.setVisible(is_direct)
         self.model_detail_panel.setVisible(is_direct)
         self.direct_role_panel.setVisible(is_direct)