feat(web): add terminal toggle button to chat header

apps/web/src/components/ChatView.tsx

@@ -1026,6 +1026,10 @@ export default function ChatView({ threadId }: ChatViewProps) {
     () => shortcutLabelForCommand(keybindings, "terminal.split"),
     [keybindings],
   );
+  const terminalToggleShortcutLabel = useMemo(
+    () => shortcutLabelForCommand(keybindings, "terminal.toggle"),
+    [keybindings],
+  );
   const newTerminalShortcutLabel = useMemo(
     () => shortcutLabelForCommand(keybindings, "terminal.new"),
     [keybindings],
@@ -3238,6 +3242,9 @@ export default function ChatView({ threadId }: ChatViewProps) {
           }
           keybindings={keybindings}
           availableEditors={availableEditors}
+          terminalAvailable={activeProject !== undefined}
+          terminalOpen={terminalState.terminalOpen}
+          terminalToggleShortcutLabel={terminalToggleShortcutLabel}
           diffToggleShortcutLabel={diffPanelShortcutLabel}
           gitCwd={gitCwd}
           diffOpen={diffOpen}
@@ -3247,6 +3254,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
           onAddProjectScript={saveProjectScript}
           onUpdateProjectScript={updateProjectScript}
           onDeleteProjectScript={deleteProjectScript}
+          onToggleTerminal={toggleTerminalVisibility}
           onToggleDiff={onToggleDiff}
         />
       </header>

apps/web/src/components/chat/ChatHeader.tsx

@@ -6,7 +6,7 @@ import {
 } from "@t3tools/contracts";
 import { memo } from "react";
 import GitActionsControl from "../GitActionsControl";
-import { DiffIcon } from "lucide-react";
+import { DiffIcon, TerminalSquareIcon } from "lucide-react";
 import { Badge } from "../ui/badge";
 import { Tooltip, TooltipPopup, TooltipTrigger } from "../ui/tooltip";
 import ProjectScriptsControl, { type NewProjectScriptInput } from "../ProjectScriptsControl";
@@ -24,13 +24,17 @@ interface ChatHeaderProps {
   preferredScriptId: string | null;
   keybindings: ResolvedKeybindingsConfig;
   availableEditors: ReadonlyArray<EditorId>;
+  terminalAvailable: boolean;
+  terminalOpen: boolean;
+  terminalToggleShortcutLabel: string | null;
   diffToggleShortcutLabel: string | null;
   gitCwd: string | null;
   diffOpen: boolean;
   onRunProjectScript: (script: ProjectScript) => void;
   onAddProjectScript: (input: NewProjectScriptInput) => Promise<void>;
   onUpdateProjectScript: (scriptId: string, input: NewProjectScriptInput) => Promise<void>;
   onDeleteProjectScript: (scriptId: string) => Promise<void>;
+  onToggleTerminal: () => void;
   onToggleDiff: () => void;
 }
 
@@ -44,13 +48,17 @@ export const ChatHeader = memo(function ChatHeader({
   preferredScriptId,
   keybindings,
   availableEditors,
+  terminalAvailable,
+  terminalOpen,
+  terminalToggleShortcutLabel,
   diffToggleShortcutLabel,
   gitCwd,
   diffOpen,
   onRunProjectScript,
   onAddProjectScript,
   onUpdateProjectScript,
   onDeleteProjectScript,
+  onToggleTerminal,
   onToggleDiff,
 }: ChatHeaderProps) {
   return (
@@ -94,6 +102,30 @@ export const ChatHeader = memo(function ChatHeader({
           />
         )}
         {activeProjectName && <GitActionsControl gitCwd={gitCwd} activeThreadId={activeThreadId} />}
+        <Tooltip>
+          <TooltipTrigger
+            render={
+              <Toggle
+                className="shrink-0"
+                pressed={terminalOpen}
+                onPressedChange={onToggleTerminal}
+                aria-label="Toggle terminal drawer"
+                variant="outline"
+                size="xs"
+                disabled={!terminalAvailable}
+              >
+                <TerminalSquareIcon className="size-3" />
+              </Toggle>
+            }
+          />
+          <TooltipPopup side="bottom">
+            {!terminalAvailable
+              ? "Terminal is unavailable until this thread has an active project."
+              : terminalToggleShortcutLabel
+                ? `Toggle terminal drawer (${terminalToggleShortcutLabel})`
+                : "Toggle terminal drawer"}
+          </TooltipPopup>
+        </Tooltip>
         <Tooltip>
           <TooltipTrigger
             render={