v2.4.1: Replace raw wrapper script editor with structured config UI

Replace the raw textarea script editor with a structured form for Java
wrapper configuration. Users now manage two lists (JVM flags to strip,
args to inject with server/always condition) instead of editing bash/batch
scripts directly. Scripts are generated at launch time from the structured
config. Includes collapsible script preview for power users.

backend/core/config.js

@@ -858,6 +858,212 @@ function checkLaunchReady() {
   };
 }
 
+// =============================================================================
+// JAVA WRAPPER CONFIGURATION (Structured)
+// =============================================================================
+
+const DEFAULT_WRAPPER_CONFIG = {
+  stripFlags: ['-XX:+UseCompactObjectHeaders'],
+  injectArgs: [
+    { arg: '--disable-sentry', condition: 'server' }
+  ]
+};
+
+function getDefaultWrapperConfig() {
+  return JSON.parse(JSON.stringify(DEFAULT_WRAPPER_CONFIG));
+}
+
+function loadWrapperConfig() {
+  const config = loadConfig();
+  if (config.javaWrapperConfig && typeof config.javaWrapperConfig === 'object') {
+    const wc = config.javaWrapperConfig;
+    if (Array.isArray(wc.stripFlags) && Array.isArray(wc.injectArgs)) {
+      const loaded = JSON.parse(JSON.stringify(wc));
+      // Normalize entries: ensure every injectArg has a valid condition
+      for (const entry of loaded.injectArgs) {
+        if (!['server', 'always'].includes(entry.condition)) {
+          entry.condition = 'always';
+        }
+      }
+      return loaded;
+    }
+  }
+  return getDefaultWrapperConfig();
+}
+
+function saveWrapperConfig(wrapperConfig) {
+  if (!wrapperConfig || typeof wrapperConfig !== 'object') {
+    throw new Error('Invalid wrapper config');
+  }
+  if (!Array.isArray(wrapperConfig.stripFlags) || !Array.isArray(wrapperConfig.injectArgs)) {
+    throw new Error('Invalid wrapper config structure');
+  }
+  // Validate injectArgs entries
+  for (const entry of wrapperConfig.injectArgs) {
+    if (!entry.arg || typeof entry.arg !== 'string') {
+      throw new Error('Each inject arg must have a string "arg" property');
+    }
+    if (!['server', 'always'].includes(entry.condition)) {
+      throw new Error('Inject arg condition must be "server" or "always"');
+    }
+  }
+  saveConfig({ javaWrapperConfig: wrapperConfig });
+  console.log('[Config] Wrapper config saved');
+}
+
+function resetWrapperConfig() {
+  const config = loadConfig();
+  delete config.javaWrapperConfig;
+  delete config.javaWrapperScripts; // Clean up legacy key if present
+
+  // Write the cleaned config using the same atomic pattern as saveConfig.
+  // We cannot use saveConfig() here because it merges (spread) which cannot remove keys.
+  const data = JSON.stringify(config, null, 2);
+  fs.writeFileSync(CONFIG_TEMP, data, 'utf8');
+  if (fs.existsSync(CONFIG_FILE)) {
+    fs.copyFileSync(CONFIG_FILE, CONFIG_BACKUP);
+  }
+  fs.renameSync(CONFIG_TEMP, CONFIG_FILE);
+  console.log('[Config] Wrapper config reset to default');
+  return getDefaultWrapperConfig();
+}
+
+/**
+ * Generate a platform-specific wrapper script from structured config
+ * @param {Object} config - { stripFlags: string[], injectArgs: {arg, condition}[] }
+ * @param {string} platform - 'darwin', 'win32', or 'linux'
+ * @param {string|null} javaBin - Path to real java binary (required for darwin/linux)
+ * @returns {string} Generated script content
+ */
+function generateWrapperScript(config, platform, javaBin) {
+  const { stripFlags, injectArgs } = config;
+  const alwaysArgs = injectArgs.filter(a => a.condition === 'always');
+  const serverArgs = injectArgs.filter(a => a.condition === 'server');
+
+  if (platform === 'win32') {
+    return _generateWindowsWrapper(stripFlags, alwaysArgs, serverArgs);
+  } else {
+    return _generateUnixWrapper(stripFlags, alwaysArgs, serverArgs, javaBin);
+  }
+}
+
+function _generateUnixWrapper(stripFlags, alwaysArgs, serverArgs, javaBin) {
+  const lines = [
+    '#!/bin/bash',
+    '# Java wrapper - generated by HytaleF2P launcher',
+    `REAL_JAVA="${javaBin || '${JAVA_BIN}'}"`,
+    'ARGS=("$@")',
+    ''
+  ];
+
+  // Strip flags
+  if (stripFlags.length > 0) {
+    lines.push('# Strip JVM flags');
+    lines.push('FILTERED_ARGS=()');
+    lines.push('for arg in "${ARGS[@]}"; do');
+    lines.push('  case "$arg" in');
+    for (const flag of stripFlags) {
+      lines.push(`    "${flag}") echo "[Wrapper] Stripped: $arg" ;;`);
+    }
+    lines.push('    *) FILTERED_ARGS+=("$arg") ;;');
+    lines.push('  esac');
+    lines.push('done');
+  } else {
+    lines.push('FILTERED_ARGS=("${ARGS[@]}")');
+  }
+  lines.push('');
+
+  // Always-inject args
+  if (alwaysArgs.length > 0) {
+    lines.push('# Inject args (always)');
+    for (const a of alwaysArgs) {
+      lines.push(`FILTERED_ARGS+=("${a.arg}")`);
+      lines.push(`echo "[Wrapper] Injected ${a.arg}"`);
+    }
+    lines.push('');
+  }
+
+  // Server-conditional args (appended after HytaleServer.jar if present)
+  if (serverArgs.length > 0) {
+    lines.push('# Inject args (server only)');
+    lines.push('IS_SERVER=false');
+    lines.push('for arg in "${FILTERED_ARGS[@]}"; do');
+    lines.push('  if [[ "$arg" == *"HytaleServer.jar"* ]]; then');
+    lines.push('    IS_SERVER=true');
+    lines.push('    break');
+    lines.push('  fi');
+    lines.push('done');
+    lines.push('if [ "$IS_SERVER" = true ]; then');
+    for (const a of serverArgs) {
+      lines.push(`  FILTERED_ARGS+=("${a.arg}")`);
+      lines.push(`  echo "[Wrapper] Injected ${a.arg}"`);
+    }
+    lines.push('fi');
+    lines.push('');
+  }
+
+  lines.push('echo "[Wrapper] Executing: $REAL_JAVA ${FILTERED_ARGS[*]}"');
+  lines.push('exec "$REAL_JAVA" "${FILTERED_ARGS[@]}"');
+  lines.push('');
+
+  return lines.join('\n');
+}
+
+function _generateWindowsWrapper(stripFlags, alwaysArgs, serverArgs) {
+  const lines = [
+    '@echo off',
+    'setlocal EnableDelayedExpansion',
+    '',
+    'REM Java wrapper - generated by HytaleF2P launcher',
+    'set "REAL_JAVA=%~dp0java-original.exe"',
+    'set "ARGS=%*"',
+    ''
+  ];
+
+  // Strip flags using string replacement
+  if (stripFlags.length > 0) {
+    lines.push('REM Strip JVM flags');
+    for (const flag of stripFlags) {
+      lines.push(`set "ARGS=!ARGS:${flag}=!"`);
+    }
+    lines.push('');
+  }
+
+  // Always-inject args
+  const alwaysExtra = alwaysArgs.map(a => a.arg).join(' ');
+
+  // Server-conditional args
+  if (serverArgs.length > 0) {
+    const serverExtra = serverArgs.map(a => a.arg).join(' ');
+    lines.push('REM Check if running HytaleServer.jar and inject server args');
+    lines.push('echo !ARGS! | findstr /i "HytaleServer.jar" >nul 2>&1');
+    lines.push('if "!ERRORLEVEL!"=="0" (');
+    if (alwaysExtra) {
+      lines.push(`    echo [Wrapper] Injected ${alwaysExtra} ${serverExtra}`);
+      lines.push(`    "%REAL_JAVA%" !ARGS! ${alwaysExtra} ${serverExtra}`);
+    } else {
+      lines.push(`    echo [Wrapper] Injected ${serverExtra}`);
+      lines.push(`    "%REAL_JAVA%" !ARGS! ${serverExtra}`);
+    }
+    lines.push(') else (');
+    if (alwaysExtra) {
+      lines.push(`    "%REAL_JAVA%" !ARGS! ${alwaysExtra}`);
+    } else {
+      lines.push('    "%REAL_JAVA%" !ARGS!');
+    }
+    lines.push(')');
+  } else if (alwaysExtra) {
+    lines.push(`"%REAL_JAVA%" !ARGS! ${alwaysExtra}`);
+  } else {
+    lines.push('"%REAL_JAVA%" !ARGS!');
+  }
+
+  lines.push('exit /b !ERRORLEVEL!');
+  lines.push('');
+
+  return lines.join('\r\n');
+}
+
 // =============================================================================
 // EXPORTS
 // =============================================================================
@@ -924,6 +1130,13 @@ module.exports = {
   saveVersionBranch,
   loadVersionBranch,
 
+  // Java Wrapper Config
+  getDefaultWrapperConfig,
+  loadWrapperConfig,
+  saveWrapperConfig,
+  resetWrapperConfig,
+  generateWrapperScript,
+
   // Constants
   CONFIG_FILE,
   UUID_STORE_FILE