fix: Fetch error shown as string (not [object Object]); extract API error from response body; guard fetch availability

src/main.ts

@@ -504,14 +504,25 @@ export default function () {
 
   // UI asks to list models for a provider. Network must run here (main thread) —
   // the plugin UI iframe is CSP-sandboxed and cannot fetch external URLs.
-  on('FETCH_MODELS', async function (payload: { baseUrl: string, apiKey: string }) {
+  on('FETCH_MODELS', async function (payload: any) {
     try {
+      if (typeof fetch !== 'function') {
+        emit('MODELS_RESULT', { ok: false, error: 'fetch is not available in the plugin main thread', models: [] })
+        return
+      }
       const base = payload.baseUrl.replace(/\/+$/, '')
       const res = await fetch(base + '/models', {
         headers: { Authorization: 'Bearer ' + payload.apiKey }
       })
       if (!res.ok) {
-        emit('MODELS_RESULT', { ok: false, error: 'HTTP ' + res.status, models: [] })
+        let msg = 'HTTP ' + res.status
+        try {
+          const body = JSON.parse(await res.text())
+          if (body != null && body.error != null) {
+            msg = typeof body.error === 'string' ? body.error : (body.error.message || JSON.stringify(body.error))
+          }
+        } catch (e) { /* keep HTTP status message */ }
+        emit('MODELS_RESULT', { ok: false, error: msg, models: [] })
         return
       }
       const json: any = await res.json()
@@ -523,7 +534,8 @@ export default function () {
       }
       emit('MODELS_RESULT', { ok: true, models })
     } catch (e) {
-      emit('MODELS_RESULT', { ok: false, error: String(e), models: [] })
+      const msg = e instanceof Error ? e.message : (e != null ? String(e) : 'Unknown error')
+      emit('MODELS_RESULT', { ok: false, error: msg, models: [] })
     }
   })
 

src/ui.tsx

@@ -29,7 +29,7 @@ const MIN_WINDOW_SIZE = { width: 320, height: 200 }
 // very high — actual clamp is done by main via clampWindowSize (bounds*zoom).
 
 // Full plugin version shown in the footer status bar. Keep in sync with package.json "version".
-const PLUGIN_VERSION = '0.1.5'
+const PLUGIN_VERSION = '0.1.6'
 
 const fieldStyle = {
   display: 'flex',
@@ -90,7 +90,13 @@ function SettingsPanel (props: { settings: Settings, setSettings: (s: Settings)
 
   useEffect(function () {
     const dispose = on('MODELS_RESULT', function (payload: { ok: boolean, models: string[], error?: string }) {
-      if (!payload.ok) { setModelsError(payload.error != null ? payload.error : 'Failed to load models'); return }
+      if (!payload.ok) {
+        const msg = payload.error != null
+          ? (typeof payload.error === 'string' ? payload.error : JSON.stringify(payload.error))
+          : 'Failed to load models'
+        setModelsError(msg)
+        return
+      }
       setModelsError(null)
       const prev = settingsRef.current
       if (prev.providers[0] == null) return