Add Windows and portable installation support for Python path resolution

- Add resolvePythonPath() function that handles:
  - PYTHON_PATH env var override (highest priority)
  - Portable installations (python_embeded/python.exe)
  - Standard venv with correct paths per OS:
    - Windows: .venv/Scripts/python.exe
    - Unix: .venv/bin/python
- Remove hardcoded Unix paths from acestep.ts and generate.ts
- Remove hardcoded /home/ambsd default path

Fixes "ENOENT" errors on Windows when spawning Python processes.

server/src/routes/generate.ts

@@ -14,6 +14,7 @@ import {
   cleanupJob,
   getJobRawResponse,
   downloadAudioToBuffer,
+  resolvePythonPath,
 } from '../services/acestep.js';
 import { getStorageProvider } from '../services/storage/factory.js';
 
@@ -557,12 +558,12 @@ router.post('/format', authMiddleware, async (req: AuthenticatedRequest, res: Re
 
     const { spawn } = await import('child_process');
 
-    const ACESTEP_DIR = process.env.ACESTEP_PATH || '/home/ambsd/Desktop/aceui/ACE-Step-1.5';
+    const ACESTEP_DIR = process.env.ACESTEP_PATH || path.resolve(path.dirname(fileURLToPath(import.meta.url)), '../../../../ACE-Step-1.5');
     const __filename = fileURLToPath(import.meta.url);
     const __dirname = path.dirname(__filename);
     const SCRIPTS_DIR = path.join(__dirname, '../../scripts');
     const FORMAT_SCRIPT = path.join(SCRIPTS_DIR, 'format_sample.py');
-    const pythonPath = path.join(ACESTEP_DIR, '.venv', 'bin', 'python');
+    const pythonPath = resolvePythonPath(ACESTEP_DIR);
 
     const args = [
       FORMAT_SCRIPT,

server/src/services/acestep.ts

@@ -1,5 +1,6 @@
-import { writeFile, mkdir, copyFile, rm, stat } from 'fs/promises';
+import { writeFile, mkdir, copyFile, rm, stat, access } from 'fs/promises';
 import { spawn, execSync } from 'child_process';
+import { existsSync } from 'fs';
 import path from 'path';
 
 // Get audio duration using ffprobe
@@ -35,6 +36,29 @@ function resolveAceStepPath(): string {
   return path.resolve(__dirname, '../../../../ACE-Step-1.5');
 }
 
+// Resolve Python path cross-platform (supports venv and portable installations)
+export function resolvePythonPath(baseDir: string): string {
+  // Allow explicit override via env var
+  if (process.env.PYTHON_PATH) {
+    return process.env.PYTHON_PATH;
+  }
+
+  const isWindows = process.platform === 'win32';
+  const pythonExe = isWindows ? 'python.exe' : 'python';
+
+  // Check for portable installation first (python_embeded)
+  const portablePath = path.join(baseDir, 'python_embeded', pythonExe);
+  if (existsSync(portablePath)) {
+    return portablePath;
+  }
+
+  // Standard venv path (different structure on Windows vs Unix)
+  if (isWindows) {
+    return path.join(baseDir, '.venv', 'Scripts', pythonExe);
+  }
+  return path.join(baseDir, '.venv', 'bin', 'python');
+}
+
 const ACESTEP_DIR = resolveAceStepPath();
 const SCRIPTS_DIR = path.join(__dirname, '../../scripts');
 const PYTHON_SCRIPT = path.join(SCRIPTS_DIR, 'simple_generate.py');
@@ -431,8 +455,7 @@ interface PythonResult {
 
 function runPythonGeneration(scriptArgs: string[]): Promise<PythonResult> {
   return new Promise((resolve) => {
-    // Use the ACE-Step venv's Python directly
+    const pythonPath = resolvePythonPath(ACESTEP_DIR);
-    const pythonPath = path.join(ACESTEP_DIR, '.venv', 'bin', 'python');
     const args = [PYTHON_SCRIPT, ...scriptArgs];
 
     const proc = spawn(pythonPath, args, {