Auto-detect default INI files by OS prefix

Scan the browse directory for case-insensitive android*/linux*/lakka* .ini files at startup and use the first match, with legacy default filenames as fallback.

src/app_config.cpp

@@ -6,8 +6,12 @@
 #include "app_config.h"
 #include "ini_handler.h"
 
+#include <dirent.h>
 #include <sys/stat.h>
+#include <algorithm>
+#include <cctype>
 #include <cstring>
+#include <vector>
 
 // Create parent directories for a file path
 static void ensureParentDir(const std::string& filePath)
@@ -30,6 +34,70 @@ static void ensureParentDir(const std::string& filePath)
     mkdir(dir.c_str(), 0755);
 }
 
+static std::string toLowerCopy(const std::string& s)
+{
+    std::string out = s;
+    std::transform(out.begin(), out.end(), out.begin(),
+        [](unsigned char c) { return (char)std::tolower(c); });
+    return out;
+}
+
+static bool hasIniExtension(const std::string& name)
+{
+    if (name.size() < 4)
+        return false;
+    std::string ext = toLowerCopy(name.substr(name.size() - 4));
+    return ext == ".ini";
+}
+
+static bool startsWithCaseInsensitive(const std::string& value, const std::string& prefix)
+{
+    if (value.size() < prefix.size())
+        return false;
+    std::string valuePrefix = toLowerCopy(value.substr(0, prefix.size()));
+    return valuePrefix == toLowerCopy(prefix);
+}
+
+static std::string findIniByPrefix(const std::string& directory, const std::string& prefix, const std::string& fallbackPath)
+{
+    DIR* dp = opendir(directory.c_str());
+    if (!dp)
+        return fallbackPath;
+
+    std::vector<std::string> matches;
+    struct dirent* ep;
+
+    while ((ep = readdir(dp)) != nullptr)
+    {
+        std::string name = ep->d_name;
+        if (name == "." || name == "..")
+            continue;
+
+        if (!hasIniExtension(name))
+            continue;
+
+        if (!startsWithCaseInsensitive(name, prefix))
+            continue;
+
+        matches.push_back(name);
+    }
+
+    closedir(dp);
+
+    if (matches.empty())
+        return fallbackPath;
+
+    std::sort(matches.begin(), matches.end(), [](const std::string& a, const std::string& b) {
+        return toLowerCopy(a) < toLowerCopy(b);
+    });
+
+    std::string fullPath = directory;
+    if (!fullPath.empty() && fullPath.back() != '/')
+        fullPath += '/';
+    fullPath += matches.front();
+    return fullPath;
+}
+
 AppConfig& AppConfig::get()
 {
     static AppConfig instance;
@@ -38,10 +106,10 @@ AppConfig& AppConfig::get()
 
 AppConfig::AppConfig()
 {
-    // Defaults
-    paths[(int)OsTarget::ANDROID] = DEFAULT_ANDROID_INI;
-    paths[(int)OsTarget::LINUX]   = DEFAULT_LINUX_INI;
-    paths[(int)OsTarget::LAKKA]   = DEFAULT_LAKKA_INI;
+    // Defaults: scan for case-insensitive prefixes first, fallback to legacy names.
+    paths[(int)OsTarget::ANDROID] = findIniByPrefix(DEFAULT_BROWSE_DIR, "android", DEFAULT_ANDROID_INI);
+    paths[(int)OsTarget::LINUX]   = findIniByPrefix(DEFAULT_BROWSE_DIR, "linux", DEFAULT_LINUX_INI);
+    paths[(int)OsTarget::LAKKA]   = findIniByPrefix(DEFAULT_BROWSE_DIR, "lakka", DEFAULT_LAKKA_INI);
 }
 
 void AppConfig::load()