fix: evitar error CORS al expirar sesión de Authentik

Cuando la sesión de Authentik expira, los fetch() a /api/music recibían
un redirect (302) a la página de login. Por defecto, fetch intenta seguir
el redirect pero falla por CORS porque Authentik no tiene el header
Access-Control-Allow-Origin.

La solución es usar redirect: 'error' en todos los fetch() a endpoints
protegidos, lo que convierte los redirects en errores que podemos capturar
y manejar apropiadamente. Esto coincide con la estrategia que ya usa
useAuth.ts.

Cambios:
- stores/music.ts: Agregar redirect: 'error' a fetchTracks() y cacheByName()
- pages/index.vue: Agregar redirect: 'error' a playTrack()
- Mejorar detección de errores de autenticación para incluir 'Failed to fetch'
  y errores de tipo TypeError relacionados con redirects

stores/music.ts

@@ -44,17 +44,22 @@ export const useMusicStore = defineStore('music', {
       this.loading = true
       this.error = null
       try {
-        const response = await $fetch<{ tracks: Track[] }>('/api/music')
+        const response = await $fetch<{ tracks: Track[] }>('/api/music', {
+          credentials: 'include',
+          redirect: 'error' // No seguir redirects de Authentik - convertir en error
+        })
         this.tracks = response.tracks || []
       } catch (e: any) {
         const errorMsg = e?.message || 'Failed to load tracks'
         this.error = errorMsg
 
-        // Check if it's an auth error
+        // Check if it's an auth error (including redirect attempts from Authentik)
         if (e?.statusCode === 401 || e?.statusCode === 403 ||
             errorMsg.includes('401') || errorMsg.includes('403') ||
-            errorMsg.includes('Unauthorized')) {
-          console.warn('[Music Store] Authentication error detected')
+            errorMsg.includes('Unauthorized') ||
+            errorMsg.includes('Failed to fetch') ||
+            (e?.cause?.name === 'TypeError' && e?.cause?.message?.includes('redirect'))) {
+          console.warn('[Music Store] Authentication error detected:', errorMsg)
           // The useAuth composable will be notified via watch in components
         }
       } finally {
@@ -128,7 +133,10 @@ export const useMusicStore = defineStore('music', {
     async cacheByName(name: string, duration?: number): Promise<boolean> {
       try {
         const encodedName = encodeURIComponent(name)
-        const response = await fetch(`/api/music/${encodedName}`)
+        const response = await fetch(`/api/music/${encodedName}`, {
+          credentials: 'include',
+          redirect: 'error' // No seguir redirects de Authentik - convertir en error
+        })
 
         if (!response.ok) {
           const errorMsg = `HTTP ${response.status}`
@@ -147,9 +155,13 @@ export const useMusicStore = defineStore('music', {
         return true
       } catch (e: any) {
         console.error('[Music Store] Cache failed:', e)
-        // Propagate auth errors
-        if (e?.message?.includes('401') || e?.message?.includes('403')) {
-          this.error = e.message
+
+        // Propagate auth errors (including redirect attempts from Authentik)
+        if (e?.message?.includes('401') ||
+            e?.message?.includes('403') ||
+            e?.message?.includes('Failed to fetch') ||
+            (e?.name === 'TypeError' && e?.message?.includes('redirect'))) {
+          this.error = e.message || 'Authentication error'
         }
         return false
       }