fix: VLC discovery for desktop Gradle run task

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/service/media/BundledVlcDiscoverer.kt

@@ -21,11 +21,11 @@
 package com.vitorpamplona.amethyst.desktop.service.media
 
 import uk.co.caprica.vlcj.factory.discovery.strategy.NativeDiscoveryStrategy
-import java.io.File
 
 /**
  * Discovers bundled VLC libraries on Windows and Linux.
- * Reads the Compose application resources directory and looks for a vlc/ subdirectory.
+ * Uses [VlcResourceResolver] to find the VLC directory from the Compose application
+ * resources or development fallback paths.
  */
 class BundledVlcDiscoverer : NativeDiscoveryStrategy {
     override fun supported(): Boolean {
@@ -34,9 +34,8 @@ class BundledVlcDiscoverer : NativeDiscoveryStrategy {
     }
 
     override fun discover(): String {
-        val resourcesDir = System.getProperty("compose.application.resources.dir") ?: return ""
-        val vlcDir = File(resourcesDir, "vlc")
-        return if (vlcDir.isDirectory) vlcDir.absolutePath else ""
+        val vlcDir = VlcResourceResolver.findVlcDir() ?: return ""
+        return vlcDir.absolutePath
     }
 
     override fun onFound(path: String): Boolean = true

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/service/media/MacOsVlcDiscoverer.kt

@@ -24,11 +24,12 @@ import com.sun.jna.NativeLibrary
 import uk.co.caprica.vlcj.binding.lib.LibC
 import uk.co.caprica.vlcj.binding.support.runtime.RuntimeUtil
 import uk.co.caprica.vlcj.factory.discovery.strategy.BaseNativeDiscoveryStrategy
-import java.io.File
 
 /**
  * Discovers bundled VLC libraries on macOS.
  * Must force-load libvlccore before libvlc to avoid link errors.
+ * Uses [VlcResourceResolver] to find the VLC directory from the Compose application
+ * resources or development fallback paths.
  */
 class MacOsVlcDiscoverer :
     BaseNativeDiscoveryStrategy(
@@ -41,9 +42,8 @@ class MacOsVlcDiscoverer :
     }
 
     override fun discoveryDirectories(): List<String> {
-        val resourcesDir = System.getProperty("compose.application.resources.dir") ?: return emptyList()
-        val vlcDir = File(resourcesDir, "vlc")
-        return if (vlcDir.isDirectory) listOf(vlcDir.absolutePath) else emptyList()
+        val vlcDir = VlcResourceResolver.findVlcDir() ?: return emptyList()
+        return listOf(vlcDir.absolutePath)
     }
 
     override fun onFound(path: String): Boolean {

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/service/media/VlcResourceResolver.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.service.media
+
+import java.io.File
+
+/**
+ * Resolves the bundled VLC directory, with fallbacks for development (Gradle run).
+ *
+ * Resolution order:
+ * 1. `compose.application.resources.dir` system property (set by packaged app)
+ * 2. Gradle `prepareAppResources` build output
+ * 3. Source `appResources` directory (platform-specific)
+ */
+object VlcResourceResolver {
+    private val currentPlatform: String by lazy {
+        val os = System.getProperty("os.name").lowercase()
+        when {
+            "mac" in os || "darwin" in os -> "macos"
+            "win" in os -> "windows"
+            else -> "linux"
+        }
+    }
+
+    /**
+     * Returns the VLC directory if found, or null.
+     */
+    fun findVlcDir(): File? {
+        // 1. Compose application resources dir (packaged app or plugin-provided)
+        System.getProperty("compose.application.resources.dir")?.let { dir ->
+            val vlcDir = File(dir, "vlc")
+            if (vlcDir.isDirectory) return vlcDir
+        }
+
+        // 2. Gradle prepareAppResources build output (relative to working dir)
+        val buildOutput = File("desktopApp/build/compose/tmp/prepareAppResources/vlc")
+        if (buildOutput.isDirectory) return buildOutput
+
+        // 3. Source appResources (platform-specific subdirectory)
+        val sourceResources = File("desktopApp/src/jvmMain/appResources/$currentPlatform/vlc")
+        if (sourceResources.isDirectory) return sourceResources
+
+        return null
+    }
+}