feat: show failure message when model cannot be discovered

tui.tsx

@@ -42,6 +42,7 @@ type TrackerState = {
   generatePrevNd: number
   generateStartAt: number
   prevNdBySlot: Record<number, { baseline: number; hasIncreased: boolean }>
+  failure: string | null
 }
 
 function estimateStreamTokens(delta: string) {
@@ -200,6 +201,7 @@ function SessionPromptRight(props: {
   })
 
   const text = createMemo(() => {
+    if (props.tracker.failure) return props.tracker.failure
     const pp = prefillRate()
     const tps = liveTps()
     if (props.tracker.isPrefilling && pp) {
@@ -230,6 +232,7 @@ const tui: TuiPlugin = async (api) => {
     generatePrevNd: 0,
     generateStartAt: 0,
     prevNdBySlot: {},
+    failure: null,
   }
   const [version, setVersion] = createSignal(0)
   const [clock, setClock] = createSignal(Date.now())
@@ -294,6 +297,13 @@ const tui: TuiPlugin = async (api) => {
       }
     }
 
+    if (!model) {
+      tracker.failure = "no model found"
+      bump()
+      return
+    }
+    tracker.failure = null
+
     let anyPrefilling = false
     let anyGenerating = false
     let genEnded = false