Add first-run setup wizard and file browser for library creation

- On first start (no users in DB), show a setup page in the web UI
  to create the admin account instead of reading credentials from .env
- New public endpoints: GET /api/setup/status, POST /api/setup
- New admin endpoint: GET /api/filebrowser?path=... for directory listing
- FileBrowser modal component with navigation, used in Admin > Libraries
- Remove _seed_admin / _seed_default_library from server startup

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/App.tsx

@@ -1,10 +1,11 @@
-import React, { useEffect } from 'react'
+import React, { useEffect, useState } from 'react'
 import { BrowserRouter, Routes, Route, Navigate } from 'react-router-dom'
 import { useAuthStore } from './store/authStore'
 import { usePlayerStore } from './store/playerStore'
 import Layout from './components/common/Layout'
 import AudioPlayer from './components/player/AudioPlayer'
 import Login from './pages/Login'
+import Setup from './pages/Setup'
 import Library from './pages/Library'
 import BookDetail from './pages/BookDetail'
 import PodcastDetail from './pages/PodcastDetail'
@@ -20,8 +21,19 @@ function AppRoutes() {
   const { user, loadAuth } = useAuthStore()
   const { libraries } = useAuthStore()
   const { expanded, setExpanded } = usePlayerStore()
+  const [setupNeeded, setSetupNeeded] = useState<boolean | null>(null)
 
-  useEffect(() => { loadAuth() }, [])
+  useEffect(() => {
+    fetch('/api/setup/status')
+      .then((r) => r.json())
+      .then((d) => setSetupNeeded(d.needsSetup ?? false))
+      .catch(() => setSetupNeeded(false))
+  }, [])
+
+  useEffect(() => { if (setupNeeded === false) loadAuth() }, [setupNeeded])
+
+  if (setupNeeded === null) return <div className="min-h-screen bg-background" />
+  if (setupNeeded) return <Setup onComplete={() => setSetupNeeded(false)} />
 
   const defaultLib = libraries?.[0]?.id
 

frontend/src/components/common/FileBrowser.tsx

@@ -0,0 +1,103 @@
+import React, { useState, useEffect } from 'react'
+import { Folder, ChevronRight, ChevronUp, X, Check, Loader2 } from 'lucide-react'
+import api from '../../api/client'
+
+interface Entry { name: string; path: string; isDir: boolean }
+
+interface Props {
+  initialPath?: string
+  onSelect: (path: string) => void
+  onClose: () => void
+}
+
+export default function FileBrowser({ initialPath = '/', onSelect, onClose }: Props) {
+  const [path, setPath] = useState(initialPath)
+  const [entries, setEntries] = useState<Entry[]>([])
+  const [parent, setParent] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState('')
+
+  const load = async (p: string) => {
+    setLoading(true)
+    setError('')
+    try {
+      const r = await api.get('/api/filebrowser', { params: { path: p } })
+      setPath(r.data.path)
+      setParent(r.data.parent)
+      setEntries(r.data.entries.filter((e: Entry) => e.isDir))
+    } catch (err: any) {
+      setError(err.response?.data?.detail || 'Fehler beim Laden')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  useEffect(() => { load(initialPath) }, [])
+
+  return (
+    <div className="fixed inset-0 bg-black/70 z-50 flex items-center justify-center p-4" onClick={onClose}>
+      <div
+        className="bg-surface border border-white/10 rounded-xl w-full max-w-lg shadow-2xl flex flex-col"
+        style={{ maxHeight: '80vh' }}
+        onClick={(e) => e.stopPropagation()}
+      >
+        {/* Header */}
+        <div className="flex items-center justify-between px-4 py-3 border-b border-white/10 flex-shrink-0">
+          <h3 className="text-sm font-semibold text-white">Ordner auswählen</h3>
+          <button onClick={onClose} className="text-gray-400 hover:text-white">
+            <X size={16} />
+          </button>
+        </div>
+
+        {/* Current path */}
+        <div className="px-4 py-2 bg-white/5 border-b border-white/10 flex items-center gap-2 flex-shrink-0">
+          {parent && (
+            <button onClick={() => load(parent)} className="text-gray-400 hover:text-white flex-shrink-0">
+              <ChevronUp size={16} />
+            </button>
+          )}
+          <p className="text-xs text-gray-300 font-mono truncate">{path}</p>
+        </div>
+
+        {/* Entry list */}
+        <div className="overflow-y-auto flex-1">
+          {loading ? (
+            <div className="flex justify-center py-10">
+              <Loader2 size={24} className="text-primary animate-spin" />
+            </div>
+          ) : error ? (
+            <p className="text-red-400 text-sm px-4 py-6">{error}</p>
+          ) : entries.length === 0 ? (
+            <p className="text-gray-500 text-sm px-4 py-6">Keine Unterordner</p>
+          ) : (
+            entries.map((e) => (
+              <button
+                key={e.path}
+                onClick={() => load(e.path)}
+                className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-white/5 text-gray-300 hover:text-white text-sm text-left transition-colors"
+              >
+                <Folder size={16} className="text-yellow-500 flex-shrink-0" />
+                <span className="flex-1 truncate">{e.name}</span>
+                <ChevronRight size={14} className="flex-shrink-0 text-gray-600" />
+              </button>
+            ))
+          )}
+        </div>
+
+        {/* Footer */}
+        <div className="flex items-center justify-between px-4 py-3 border-t border-white/10 flex-shrink-0">
+          <button onClick={onClose} className="text-gray-400 text-sm hover:text-white">
+            Abbrechen
+          </button>
+          <button
+            onClick={() => { onSelect(path); onClose() }}
+            className="flex items-center gap-2 bg-primary text-black px-4 py-2 rounded-lg text-sm font-medium hover:bg-primary/80"
+          >
+            <Check size={14} />
+            Auswählen
+          </button>
+        </div>
+      </div>
+    </div>
+  )
+}

frontend/src/pages/Admin.tsx

@@ -1,7 +1,8 @@
 import React, { useEffect, useState } from 'react'
-import { Users, Library, Settings, Trash2, Plus, RefreshCw, Loader2, Check, X } from 'lucide-react'
+import { Users, Library, Settings, Trash2, Plus, RefreshCw, Loader2, Check, X, FolderOpen } from 'lucide-react'
 import { getUsers, createUser, deleteUser, getSettings, updateSettings } from '../api/me'
 import { getLibraries, scanLibrary, createLibrary, deleteLibrary } from '../api/libraries'
+import FileBrowser from '../components/common/FileBrowser'
 
 type Tab = 'users' | 'libraries' | 'settings'
 
@@ -119,6 +120,7 @@ function LibrariesPanel() {
   const [loading, setLoading] = useState(true)
   const [scanning, setScanning] = useState<string | null>(null)
   const [showCreate, setShowCreate] = useState(false)
+  const [showBrowser, setShowBrowser] = useState(false)
   const [form, setForm] = useState({ name: '', path: '', mediaType: 'book' })
 
   useEffect(() => { getLibraries().then(setLibraries).finally(() => setLoading(false)) }, [])
@@ -160,10 +162,27 @@ function LibrariesPanel() {
             value={form.name} onChange={(e) => setForm({ ...form, name: e.target.value })}
             className="w-full bg-white/5 border border-white/10 rounded-lg px-3 py-2 text-sm text-white placeholder-gray-500 focus:outline-none focus:ring-1 focus:ring-primary"
           />
-          <input type="text" placeholder="Pfad (z.B. /audiofiles/hörbucher)"
-            value={form.path} onChange={(e) => setForm({ ...form, path: e.target.value })}
-            className="w-full bg-white/5 border border-white/10 rounded-lg px-3 py-2 text-sm text-white placeholder-gray-500 focus:outline-none focus:ring-1 focus:ring-primary"
-          />
+          <div className="flex gap-2">
+            <input type="text" placeholder="Pfad (z.B. /audiofiles)"
+              value={form.path} onChange={(e) => setForm({ ...form, path: e.target.value })}
+              className="flex-1 bg-white/5 border border-white/10 rounded-lg px-3 py-2 text-sm text-white placeholder-gray-500 focus:outline-none focus:ring-1 focus:ring-primary"
+            />
+            <button
+              type="button"
+              onClick={() => setShowBrowser(true)}
+              className="flex items-center gap-1.5 bg-white/5 border border-white/10 px-3 py-2 rounded-lg text-sm text-gray-300 hover:text-white hover:bg-white/10"
+            >
+              <FolderOpen size={14} />
+              Durchsuchen
+            </button>
+          </div>
+          {showBrowser && (
+            <FileBrowser
+              initialPath={form.path || '/'}
+              onSelect={(p) => setForm({ ...form, path: p })}
+              onClose={() => setShowBrowser(false)}
+            />
+          )}
           <select value={form.mediaType} onChange={(e) => setForm({ ...form, mediaType: e.target.value })}
             className="w-full bg-white/5 border border-white/10 rounded-lg px-3 py-2 text-sm text-gray-300 focus:outline-none">
             <option value="book">Hörbücher</option>

frontend/src/pages/Setup.tsx

@@ -0,0 +1,84 @@
+import React, { useState } from 'react'
+import { BookOpen, Loader2, Eye, EyeOff } from 'lucide-react'
+import api from '../api/client'
+
+interface Props {
+  onComplete: () => void
+}
+
+export default function Setup({ onComplete }: Props) {
+  const [username, setUsername] = useState('')
+  const [password, setPassword] = useState('')
+  const [showPwd, setShowPwd] = useState(false)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState('')
+
+  const submit = async (e: React.FormEvent) => {
+    e.preventDefault()
+    setError('')
+    setLoading(true)
+    try {
+      await api.post('/api/setup', { username, password })
+      onComplete()
+    } catch (err: any) {
+      setError(err.response?.data?.detail || 'Fehler beim Anlegen')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <div className="min-h-screen bg-background flex items-center justify-center p-4">
+      <div className="w-full max-w-sm">
+        <div className="flex items-center justify-center gap-3 mb-3">
+          <BookOpen className="text-primary" size={32} />
+          <h1 className="text-3xl font-bold text-white">Audiolib</h1>
+        </div>
+        <p className="text-center text-gray-400 text-sm mb-8">Erster Start — Admin-Konto anlegen</p>
+
+        <form onSubmit={submit} className="bg-surface rounded-xl p-6 space-y-4">
+          <div>
+            <label className="block text-sm text-gray-400 mb-1">Benutzername</label>
+            <input
+              type="text"
+              value={username}
+              onChange={(e) => setUsername(e.target.value)}
+              className="w-full bg-white/5 border border-white/10 rounded-lg px-3 py-2 text-white placeholder-gray-500 focus:outline-none focus:ring-1 focus:ring-primary"
+              placeholder="admin"
+              autoFocus
+            />
+          </div>
+          <div>
+            <label className="block text-sm text-gray-400 mb-1">Passwort</label>
+            <div className="relative">
+              <input
+                type={showPwd ? 'text' : 'password'}
+                value={password}
+                onChange={(e) => setPassword(e.target.value)}
+                className="w-full bg-white/5 border border-white/10 rounded-lg px-3 py-2 pr-10 text-white placeholder-gray-500 focus:outline-none focus:ring-1 focus:ring-primary"
+                placeholder="••••••••"
+              />
+              <button
+                type="button"
+                onClick={() => setShowPwd(!showPwd)}
+                className="absolute right-3 top-1/2 -translate-y-1/2 text-gray-400 hover:text-white"
+                tabIndex={-1}
+              >
+                {showPwd ? <EyeOff size={16} /> : <Eye size={16} />}
+              </button>
+            </div>
+          </div>
+          {error && <p className="text-red-400 text-sm">{error}</p>}
+          <button
+            type="submit"
+            disabled={loading || !username || !password}
+            className="w-full bg-primary text-black font-semibold py-2.5 rounded-lg hover:bg-primary/80 disabled:opacity-50 disabled:cursor-not-allowed flex items-center justify-center gap-2"
+          >
+            {loading && <Loader2 size={16} className="animate-spin" />}
+            Konto anlegen
+          </button>
+        </form>
+      </div>
+    </div>
+  )
+}