Remove agent cycling and enhance model selector display

- Remove Tab/Shift+Tab shortcuts for cycling agents
- Remove Next/Previous Agent commands from command palette
- Remove handleCycleAgent and handleCycleAgentReverse functions
- Remove Tab keyboard hint from agent selector UI
- Enhance model selector to show provider/modelId below model name
- Widen model selector button to accommodate additional text

src/components/agent-selector.tsx

@@ -102,16 +102,9 @@ export default function AgentSelector(props: AgentSelectorProps) {
           </Select.Content>
         </Select.Portal>
       </Select>
-      <div class="flex items-center gap-1">
-        <Show when={availableAgents().length > 1}>
-          <span class="text-xs text-gray-400">
-            <Kbd>Tab</Kbd>
-          </span>
-        </Show>
-        <span class="text-xs text-gray-400">
-          <Kbd shortcut="cmd+shift+a" />
-        </span>
-      </div>
+      <span class="text-xs text-gray-400">
+        <Kbd shortcut="cmd+shift+a" />
+      </span>
     </div>
   )
 }

src/components/model-selector.tsx

@@ -101,10 +101,17 @@ export default function ModelSelector(props: ModelSelectorProps) {
           <Combobox.Input class="sr-only" data-model-selector />
           <Combobox.Trigger
             ref={triggerRef}
-            class="inline-flex items-center justify-between gap-2 px-2 py-1 bg-white border border-gray-300 rounded hover:bg-gray-50 outline-none focus:ring-2 focus:ring-blue-500 text-xs min-w-[140px]"
+            class="inline-flex items-center justify-between gap-2 px-2 py-1 bg-white border border-gray-300 rounded hover:bg-gray-50 outline-none focus:ring-2 focus:ring-blue-500 text-xs min-w-[180px]"
           >
-            <span class="text-gray-700">Model: {currentModelValue()?.name ?? "None"}</span>
-            <Combobox.Icon>
+            <div class="flex flex-col items-start min-w-0">
+              <span class="text-gray-700 font-medium">Model: {currentModelValue()?.name ?? "None"}</span>
+              {currentModelValue() && (
+                <span class="text-gray-500 text-[10px]">
+                  {currentModelValue()!.providerId}/{currentModelValue()!.id}
+                </span>
+              )}
+            </div>
+            <Combobox.Icon class="flex-shrink-0">
               <ChevronDown class="w-3 h-3 text-gray-500" />
             </Combobox.Icon>
           </Combobox.Trigger>