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/lib/shortcuts/agent.ts

@@ -1,39 +1,8 @@
 import { keyboardRegistry } from "../keyboard-registry"
 
-export function registerAgentShortcuts(
-  cycleAgent: () => void,
-  cycleAgentReverse: () => void,
-  focusModelSelector: () => void,
-  openAgentSelector: () => void,
-) {
+export function registerAgentShortcuts(focusModelSelector: () => void, openAgentSelector: () => void) {
   const isMac = () => navigator.platform.toLowerCase().includes("mac")
 
-  keyboardRegistry.register({
-    id: "agent-next",
-    key: "Tab",
-    modifiers: {},
-    handler: cycleAgent,
-    description: "next agent",
-    context: "global",
-    condition: () => {
-      const active = document.activeElement
-      return !(active?.tagName === "TEXTAREA" || active?.tagName === "INPUT" || active?.hasAttribute("contenteditable"))
-    },
-  })
-
-  keyboardRegistry.register({
-    id: "agent-prev",
-    key: "Tab",
-    modifiers: { shift: true },
-    handler: cycleAgentReverse,
-    description: "previous agent",
-    context: "global",
-    condition: () => {
-      const active = document.activeElement
-      return !(active?.tagName === "TEXTAREA" || active?.tagName === "INPUT" || active?.hasAttribute("contenteditable"))
-    },
-  })
-
   keyboardRegistry.register({
     id: "focus-model",
     key: "M",