feat(chat): switch execution mode from the model picker

crates/agent-gateway/web/src/app/GatewayApp.tsx

@@ -93,6 +93,7 @@ import {
   updateRightDockWidth,
   updateSkills,
   updateSshProjectHostIds,
+  updateSystem,
   type WorkspaceProject,
   workspaceProjectPathKey,
 } from "@/lib/settings";
@@ -4114,6 +4115,20 @@ export default function GatewayApp() {
                 >
                   <ChatHeader
                     settings={settings}
+                    onSelectExecutionMode={(mode) =>
+                      setSettings((prev) => {
+                        const current = prev.system.executionMode;
+                        if (mode === "text") {
+                          return current === "text"
+                            ? prev
+                            : updateSystem(prev, { executionMode: "text" });
+                        }
+                        // 切回 Agent：仅从 Chat 切换；agent-dev 视为 Agent，保持不降级。
+                        return current === "text"
+                          ? updateSystem(prev, { executionMode: "tools" })
+                          : prev;
+                      })
+                    }
                     hasModels={modelOptions.length > 0}
                     currentModelLabel={currentModelLabel}
                     modelOptions={modelOptions}

crates/agent-gateway/web/src/i18n/config.ts

@@ -168,6 +168,7 @@ export const translations: Record<Locale, Record<string, string>> = {
     "chat.expandProvider": "展开该提供商的模型",
     "chat.collapseProvider": "收起该提供商的模型",
     "chat.searchModel": "搜索模型...",
+    "chat.executionModeHint": "切换对下一条消息生效，当前对话继续",
     "chat.noModelFound": "未找到匹配的模型",
     "chat.aborted": "已取消",
     "chat.contextWindow": "上下文窗口",
@@ -2027,6 +2028,7 @@ export const translations: Record<Locale, Record<string, string>> = {
     "chat.expandProvider": "Expand provider models",
     "chat.collapseProvider": "Collapse provider models",
     "chat.searchModel": "Search models...",
+    "chat.executionModeHint": "Applies from the next message; the conversation continues",
     "chat.noModelFound": "No matching models found",
     "chat.aborted": "Cancelled",
     "chat.contextWindow": "Context Window",

crates/agent-gateway/web/src/index.css

@@ -1217,52 +1217,37 @@
   }
 
   /* Chat header model selector: grow out of the trigger with a soft slide.
-   * Radix keeps the popup mounted while the data-state="closed" animation
-   * plays, so exit stays keyframe-driven; `forwards` holds the final frame
-   * until unmount. */
+   * Base UI drives the popup lifecycle, so enter/exit are keyed off
+   * data-starting-style / data-ending-style and the transition delays
+   * unmount. */
   .model-selector-dropdown {
     /* Slide from the anchor side; flipped placement overrides per data-side. */
     --model-menu-slide-y: -6px;
-    transform-origin: var(--radix-dropdown-menu-content-transform-origin, top left);
+    transform-origin: var(--transform-origin);
+    transition:
+      opacity 0.18s cubic-bezier(0.16, 1, 0.3, 1),
+      transform 0.18s cubic-bezier(0.16, 1, 0.3, 1);
   }
 
   .model-selector-dropdown[data-side="top"] {
     --model-menu-slide-y: 6px;
   }
 
-  .model-selector-dropdown[data-state="open"] {
-    animation: modelSelectorDropdownIn 0.18s cubic-bezier(0.16, 1, 0.3, 1);
-  }
-
-  .model-selector-dropdown[data-state="closed"] {
-    animation: modelSelectorDropdownOut 0.12s cubic-bezier(0.4, 0, 1, 1) forwards;
-  }
-
-  @keyframes modelSelectorDropdownIn {
-    from {
-      opacity: 0;
-      transform: translateY(var(--model-menu-slide-y)) scale(0.96);
-    }
-    to {
-      opacity: 1;
-      transform: translateY(0) scale(1);
-    }
+  .model-selector-dropdown[data-starting-style],
+  .model-selector-dropdown[data-ending-style] {
+    opacity: 0;
+    transform: translateY(var(--model-menu-slide-y)) scale(0.96);
   }
 
-  @keyframes modelSelectorDropdownOut {
-    from {
-      opacity: 1;
-      transform: translateY(0) scale(1);
-    }
-    to {
-      opacity: 0;
-      transform: translateY(calc(var(--model-menu-slide-y) / 2)) scale(0.98);
-    }
+  .model-selector-dropdown[data-ending-style] {
+    transition-duration: 0.12s;
+    transition-timing-function: cubic-bezier(0.4, 0, 1, 1);
+    transform: translateY(calc(var(--model-menu-slide-y) / 2)) scale(0.98);
   }
 
   /* `backwards` (not `both`): a filled forwards animation would keep holding
    * transform after it ends and suppress the item highlight translate. */
-  .model-selector-dropdown[data-state="open"] .model-selector-item {
+  .model-selector-dropdown[data-open] .model-selector-item {
     animation: modelSelectorItemIn 0.18s cubic-bezier(0.16, 1, 0.3, 1) backwards;
   }
 
@@ -1289,6 +1274,7 @@
 
     .composer-reasoning-trigger,
     .composer-reasoning-trigger > svg:last-child,
+    .model-selector-dropdown,
     .model-selector-trigger,
     .model-selector-trigger svg {
       transition: none !important;