Fix tous les appels API pour utiliser getApiUrl() au lieu de process.env

Problème: Le commit précédent n'avait corrigé que api.ts, mais AudioPlayer
et page.tsx utilisaient encore directement process.env.NEXT_PUBLIC_API_URL,
ce qui ignorait la config runtime.

Fichiers corrigés:
1. lib/api.ts:
   - Export getApiUrl() pour usage externe

2. app/page.tsx:
   - Import getApiUrl
   - /api/library/scan: process.env → getApiUrl()
   - /api/library/scan/status: process.env → getApiUrl()

3. components/AudioPlayer.tsx:
   - Import getApiUrl
   - /api/audio/waveform: process.env → getApiUrl()
   - /api/audio/stream: process.env → getApiUrl()
   - /api/audio/download: process.env → getApiUrl()

Maintenant TOUS les appels API utilisent la config runtime
(window.__RUNTIME_CONFIG__) côté client.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/app/page.tsx

@@ -2,7 +2,7 @@
 
 import { useState, useMemo } from "react"
 import { useQuery } from "@tanstack/react-query"
-import { getTracks } from "@/lib/api"
+import { getTracks, getApiUrl } from "@/lib/api"
 import type { FilterParams, Track } from "@/lib/types"
 import FilterPanel from "@/components/FilterPanel"
 import AudioPlayer from "@/components/AudioPlayer"
@@ -90,7 +90,7 @@ export default function Home() {
       setIsScanning(true)
       setScanStatus("Démarrage du scan...")
 
-      const response = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/library/scan`, {
+      const response = await fetch(`${getApiUrl()}/api/library/scan`, {
         method: 'POST',
       })
 
@@ -103,7 +103,7 @@ export default function Home() {
       // Poll scan status
       const pollInterval = setInterval(async () => {
         try {
-          const statusResponse = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/library/scan/status`)
+          const statusResponse = await fetch(`${getApiUrl()}/api/library/scan/status`)
           const status = await statusResponse.json()
 
           if (!status.is_scanning) {

frontend/components/AudioPlayer.tsx

@@ -2,6 +2,7 @@
 
 import { useState, useRef, useEffect } from "react"
 import type { Track } from "@/lib/types"
+import { getApiUrl } from "@/lib/api"
 
 interface AudioPlayerProps {
   track: Track | null
@@ -79,7 +80,7 @@ export default function AudioPlayer({ track, isPlaying, onPlayingChange }: Audio
     setIsLoadingWaveform(true)
     try {
       const response = await fetch(
-        `${process.env.NEXT_PUBLIC_API_URL}/api/audio/waveform/${trackId}`
+        `${getApiUrl()}/api/audio/waveform/${trackId}`
       )
       if (response.ok) {
         const data = await response.json()
@@ -161,7 +162,7 @@ export default function AudioPlayer({ track, isPlaying, onPlayingChange }: Audio
   return (
     <div className="bg-gray-50 border-t border-gray-300 shadow-lg" style={{ height: '80px' }}>
       {/* Hidden audio element */}
-      {track && <audio ref={audioRef} src={`${process.env.NEXT_PUBLIC_API_URL}/api/audio/stream/${track.id}`} />}
+      {track && <audio ref={audioRef} src={`${getApiUrl()}/api/audio/stream/${track.id}`} />}
 
       <div className="h-full flex items-center gap-3 px-4">
         {/* Play/Pause button */}
@@ -300,7 +301,7 @@ export default function AudioPlayer({ track, isPlaying, onPlayingChange }: Audio
         {/* Download button */}
         {track && (
           <a
-            href={`${process.env.NEXT_PUBLIC_API_URL}/api/audio/download/${track.id}`}
+            href={`${getApiUrl()}/api/audio/download/${track.id}`}
             download
             className="w-8 h-8 flex items-center justify-center text-gray-600 hover:text-gray-900 transition-colors rounded hover:bg-gray-200 flex-shrink-0"
             aria-label="Download"

frontend/lib/api.ts

@@ -15,7 +15,7 @@ import type {
 } from './types'
 
 // Get API URL from runtime config (injected at container startup) or fallback to env var
-function getApiUrl(): string {
+export function getApiUrl(): string {
   if (typeof window !== 'undefined' && (window as any).__RUNTIME_CONFIG__) {
     return (window as any).__RUNTIME_CONFIG__.API_URL
   }