feat: add keyboard shortcuts for cycling agent and thinking variant

packages/ui/src/components/chat/ChatInput.tsx

@@ -575,7 +575,7 @@ export const ChatInput: React.FC<ChatInputProps> = ({ onOpenSettings, scrollToBo
             }
         }
 
-        if (e.key === 'Tab' && !showCommandAutocomplete && !showFileMention) {
+        if (e.key === 'Tab' && e.shiftKey && !showCommandAutocomplete && !showAgentAutocomplete && !showFileMention) {
             e.preventDefault();
             cycleAgent();
             return;

packages/ui/src/components/ui/HelpDialog.tsx

@@ -10,6 +10,8 @@ import { useUIStore } from "@/stores/useUIStore";
 import { useConfigStore } from "@/stores/useConfigStore";
 import {
   RiAddLine,
+  RiAiAgentLine,
+  RiAiGenerate2,
   RiArrowUpSLine,
   RiBrainAi3Line,
   RiCloseCircleLine,
@@ -106,9 +108,19 @@ export const HelpDialog: React.FC = () => {
           description: "Toggle Session Sidebar",
           icon: RiLayoutLeftLine,
         },
+        {
+          keys: ["Shift + Tab"],
+          description: "Cycle Agent (chat input)",
+          icon: RiAiAgentLine,
+        },
         {
           keys: [`Shift + ${mod} + M`],
           description: "Open Model Selector",
+          icon: RiAiGenerate2,
+        },
+        {
+          keys: [`Shift + ${mod} + T`],
+          description: "Cycle Thinking Variant",
           icon: RiBrainAi3Line,
         },
       ],
@@ -118,12 +130,12 @@ export const HelpDialog: React.FC = () => {
       items: [
         {
           keys: [`${mod} + N`],
-          description: settingsAutoCreateWorktree ? "Create new session in worktree" : "Create New Session",
+          description: settingsAutoCreateWorktree ? "Create New Session in Worktree" : "Create New Session",
           icon: settingsAutoCreateWorktree ? RiGitBranchLine : RiAddLine,
         },
         {
           keys: [`Shift + ${mod} + N`],
-          description: settingsAutoCreateWorktree ? "Create New Session" : "Create new session in worktree",
+          description: settingsAutoCreateWorktree ? "Create New Session" : "Create New Session in Worktree",
           icon: settingsAutoCreateWorktree ? RiAddLine : RiGitBranchLine,
         },
         { keys: [`${mod} + I`], description: "Focus Chat Input", icon: RiText },
@@ -173,7 +185,7 @@ export const HelpDialog: React.FC = () => {
 
   return (
       <Dialog open={isHelpDialogOpen} onOpenChange={setHelpDialogOpen}>
-      <DialogContent className="max-w-2xl">
+      <DialogContent className="max-w-2xl w-[min(42rem,calc(100vw-1.5rem))] max-h-[calc(100dvh-2rem)] flex flex-col overflow-hidden">
         <DialogHeader>
           <DialogTitle className="flex items-center gap-2">
             <RiSettings3Line className="h-5 w-5" />
@@ -184,7 +196,8 @@ export const HelpDialog: React.FC = () => {
           </DialogDescription>
         </DialogHeader>
 
-        <div className="space-y-4 mt-3">
+        <div className="flex-1 overflow-y-auto mt-3 pr-1">
+          <div className="space-y-4">
             {shortcuts.map((section) => (
               <div key={section.category}>
                 <h3 className="typography-meta font-semibold text-muted-foreground uppercase tracking-wider mb-2">
@@ -248,6 +261,7 @@ export const HelpDialog: React.FC = () => {
               </div>
             </div>
           </div>
+        </div>
       </DialogContent>
     </Dialog>
   );

packages/ui/src/hooks/useKeyboardShortcuts.ts

@@ -171,6 +171,51 @@ export const useKeyboardShortcuts = () => {
         return;
       }
 
+      // Cmd/Ctrl+Shift+T: Cycle thinking variant (same gating as Shift+M)
+      if (hasModifier(e) && e.shiftKey && e.key.toLowerCase() === 't') {
+        const {
+          isSettingsDialogOpen,
+          isCommandPaletteOpen,
+          isHelpDialogOpen,
+          isSessionSwitcherOpen,
+          isAboutDialogOpen,
+          activeMainTab,
+        } = useUIStore.getState();
+
+        if (isSettingsDialogOpen) {
+          return;
+        }
+
+        const hasOverlay = isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen;
+        const isChatActive = activeMainTab === 'chat';
+
+        if (hasOverlay || !isChatActive) {
+          return;
+        }
+
+        const configState = useConfigStore.getState();
+        const variants = configState.getCurrentModelVariants();
+        if (variants.length === 0) {
+          return;
+        }
+
+        e.preventDefault();
+        configState.cycleCurrentVariant();
+
+        const nextVariant = useConfigStore.getState().currentVariant;
+        const sessionState = useSessionStore.getState();
+        const sessionId = sessionState.currentSessionId;
+        const agentName = useConfigStore.getState().currentAgentName;
+        const providerId = useConfigStore.getState().currentProviderId;
+        const modelId = useConfigStore.getState().currentModelId;
+
+        if (sessionId && agentName && providerId && modelId) {
+          sessionState.saveAgentModelVariantForSession(sessionId, agentName, providerId, modelId, nextVariant);
+        }
+
+        return;
+      }
+
       if (e.key === 'Escape') {
         const {
           isSettingsDialogOpen,