fix: résoudre python-embed relativement à l'exe + copier runtime dans output dir

- main.rs: utiliser current_exe().parent() au lieu de ./ relatif au cwd
- build-windows.bat: étape 5b qui copie python-embed/ et backend/ dans target/release

desktop/build-windows.bat

@@ -53,7 +53,17 @@ if errorlevel 1 (
 )
 echo ✅ Build successful
 
-REM ── 6. Signer (optionnel) ─────────────────────────────────────
+REM ── 5b. Copier python-embed à côté de l'exécutable pour le dev ─────
+echo [5b/6] Copying python-embed to output dir...
+set "OUTDIR=target\x86_64-pc-windows-msvc\release"
+if exist "%OUTDIR%\python-embed" rmdir /s /q "%OUTDIR%\python-embed"
+xcopy /E /I /Q "python-embed" "%OUTDIR%\python-embed"
+REM Copier aussi le backend Python
+if not exist "%OUTDIR%\backend" mkdir "%OUTDIR%\backend"
+xcopy /E /I /Q "..\backend" "%OUTDIR%\backend"
+echo ✅ Runtime copied
+
+REM ── 6. Résultats ───────────────────────────────────────────────────
 echo [6/6] Results:
 dir /b target\release\bundle\msi\*.msi 2>nul
 dir /b target\release\bundle\nsis\*.exe 2>nul

desktop/src/main.rs

@@ -10,10 +10,17 @@ struct BackendProcess(Mutex<Option<Child>>);
 // ── Sidecar : spawn Python backend ──────────────────────────────────────────
 
 fn spawn_backend() -> Result<Child, String> {
+    // Resolve python-embed relative to the executable, not cwd
+    let exe_dir = std::env::current_exe()
+        .map_err(|e| format!("Cannot get exe path: {}", e))?
+        .parent()
+        .ok_or("Cannot get exe parent dir")?
+        .to_path_buf();
+
     let python = if cfg!(target_os = "windows") {
-        "./python-embed/python.exe"
+        exe_dir.join("python-embed").join("python.exe")
     } else {
-        "./python-embed/bin/python3"
+        exe_dir.join("python-embed").join("bin").join("python3")
     };
 
     let child = Command::new(python)