Generalize game ID normalization for all _game suffixes

Previously the system only handled the specific case of minetest_game -> minetest.
Based on Luanti developer feedback that "_game is removed from IDs as part of
normalisation for all game IDs not just MTG", this change generalizes the pattern.

## Changes Made

### Enhanced Game ID Normalization
- `mapToActualGameId()`: Now automatically removes "_game" suffix from any game ID
- `mapGameIdForWorldCreation()`: Generalizes suffix removal for world.mt files
- `mapInternalGameIdToDirectory()`: Enhanced to dynamically check filesystem for directories

### Backwards Compatibility
- All existing minetest_game -> minetest mappings continue to work
- Now also handles any other games with _game suffix (e.g., survival_game -> survival)
- Original EJS templates already compatible via world.gameTitle || world.gameid pattern

### Technical Implementation
- Replaces hardcoded mapping tables with general suffix detection
- Maintains proper fallback behavior for games without _game suffix
- Filesystem-aware directory resolution for reverse mapping

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

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

utils/paths.js

@@ -182,33 +182,72 @@ class LuantiPaths {
 
   mapToActualGameId(directoryName) {
     // Map directory names to the actual game IDs that Luanti recognizes
-    // For most cases, the directory name IS the game ID
-    const gameIdMap = {
-      // Luanti internal alias mapping - see https://github.com/luanti-org/luanti/blob/c9d4c33174c87ede1f49c5fe5e8e49a784798eb6/src/content/subgames.cpp#L21
-      'minetest_game': 'minetest',
-    };
+    // Luanti normalizes game IDs by removing "_game" suffix from all games
+    // See https://github.com/luanti-org/luanti/blob/c9d4c33174c87ede1f49c5fe5e8e49a784798eb6/src/content/subgames.cpp#L21
     
-    return gameIdMap[directoryName] || directoryName;
+    // Remove "_game" suffix if present
+    if (directoryName.endsWith('_game')) {
+      return directoryName.slice(0, -5); // Remove last 5 characters ("_game")
+    }
+    
+    return directoryName;
   }
 
   mapGameIdForWorldCreation(gameId) {
     // When creating worlds, map game IDs that Luanti expects to use different IDs internally
     // This is the reverse of directory-based detection - we're setting what goes in world.mt
-    const worldGameIdMap = {
-      'minetest_game': 'minetest',  // Luanti expects 'minetest' in world.mt even for minetest_game
-    };
+    // Luanti normalizes all game IDs by removing "_game" suffix
     
-    return worldGameIdMap[gameId] || gameId;
+    // Remove "_game" suffix if present
+    if (gameId.endsWith('_game')) {
+      return gameId.slice(0, -5); // Remove last 5 characters ("_game")
     }
     
-  mapInternalGameIdToDirectory(internalGameId) {
-    // Reverse mapping: convert internal game ID back to directory name for display/reference
-    // This helps when we read a world.mt with "minetest" but want to show "Minetest Game"
-    const reverseGameIdMap = {
-      'minetest': 'minetest_game',  // world.mt has 'minetest' but directory is 'minetest_game'
-    };
+    return gameId;
+  }
 
-    return reverseGameIdMap[internalGameId] || internalGameId;
+  async mapInternalGameIdToDirectory(internalGameId) {
+    // Reverse mapping: convert internal game ID back to directory name for display/reference
+    // This helps when we read a world.mt with normalized game ID but want to show directory name
+    // Since Luanti normalizes by removing "_game" suffix, we need to check if a directory
+    // with "_game" suffix exists for this normalized ID
+    
+    const fs = require('fs').promises;
+    const path = require('path');
+    
+    // Check both system and user games directories
+    const gameDirs = [this.getGamesPath()];
+    if (this.getSystemGamesPath() && this.getSystemGamesPath() !== this.getGamesPath()) {
+      gameDirs.push(this.getSystemGamesPath());
+    }
+    
+    for (const gameDir of gameDirs) {
+      try {
+        // First check if the internalGameId as-is exists as a directory
+        const directPath = path.join(gameDir, internalGameId);
+        const stat = await fs.stat(directPath);
+        if (stat.isDirectory()) {
+          return internalGameId;
+        }
+      } catch (error) {
+        // Directory doesn't exist, try with "_game" suffix
+      }
+      
+      try {
+        // Check if there's a directory with "_game" suffix
+        const gameIdWithSuffix = internalGameId + '_game';
+        const suffixPath = path.join(gameDir, gameIdWithSuffix);
+        const stat = await fs.stat(suffixPath);
+        if (stat.isDirectory()) {
+          return gameIdWithSuffix;
+        }
+      } catch (error) {
+        // Directory doesn't exist either
+      }
+    }
+    
+    // Fallback: return the original ID
+    return internalGameId;
   }
 
   async getInstalledGames() {